@article{BenDorNeugebauerEnzeletal.2020,
  author    = {Ben Dor, Yoav and Neugebauer, Ina and Enzel, Yehouda and Schwab, Markus J. and Tjallingii, Rik and Erel, Yigal and Brauer, Achim},
  title     = {Reply to comment on: Ben Dor, Yoav et al. : Varves of the Dead Sea sedimentary record. - In: Quaternary science reviews : the international multidisciplinary research and review journal. - 215 (2019), S. 173 - 184. - (ISSN: 0277-3791). - https://doi.org/10.1016/j.quascirev.2019.04.011},
  series = {Quaternary science reviews : the international multidisciplinary research and review journal},
  volume    = {231},
  journal   = {Quaternary science reviews : the international multidisciplinary research and review journal},
  publisher = {Elsevier},
  address   = {Amsterdam [u.a.]},
  issn      = {0277-3791},
  doi       = {10.1016/j.quascirev.2019.106063},
  pages     = {5},
  year      = {2020},
  abstract  = {In the comment on "Varves of the Dead Sea sedimentary record." Quaternary Science Reviews 215 (Ben Dor et al., 2019): 173-184. by R. Bookman, two recently published papers are suggested to prove that the interpretation of the laminated sedimentary sequence of the Dead Sea, deposited mostly during MIS2 and Holocene pluvials, as annual deposits (i.e., varves) is wrong. In the following response, we delineate several lines of evidence which coalesce to demonstrate that based on the vast majority of evidence, including some of the evidence provided in the comment itself, the interpretation of these sediments as varves is the more likely scientific conclusion. We further discuss the evidence brought up in the comment and its irrelevance and lack of robustness for addressing the question under discussion.},
  language  = {en}
}
@article{KumarHesseRaoetal.2020,
  author    = {Kumar, Rohini and Hesse, Fabienne and Rao, P. Srinivasa and Musolff, Andreas and Jawitz, James and Sarrazin, Francois and Samaniego, Luis and Fleckenstein, Jan H. and Rakovec, Oldrich and Thober, S. and Attinger, Sabine},
  title     = {Strong hydroclimatic controls on vulnerability to subsurface nitrate contamination across Europe},
  series = {Nature Communications},
  volume    = {11},
  journal   = {Nature Communications},
  number    = {1},
  publisher = {Nature Publishing Group UK},
  address   = {London},
  issn      = {2041-1723},
  doi       = {10.1038/s41467-020-19955-8},
  pages     = {1 -- 10},
  year      = {2020},
  abstract  = {Subsurface contamination due to excessive nutrient surpluses is a persistent and widespread problem in agricultural areas across Europe. The vulnerability of a particular location to pollution from reactive solutes, such as nitrate, is determined by the interplay between hydrologic transport and biogeochemical transformations. Current studies on the controls of subsurface vulnerability do not consider the transient behaviour of transport dynamics in the root zone. Here, using state-of-the-art hydrologic simulations driven by observed hydroclimatic forcing, we demonstrate the strong spatiotemporal heterogeneity of hydrologic transport dynamics and reveal that these dynamics are primarily controlled by the hydroclimatic gradient of the aridity index across Europe. Contrasting the space-time dynamics of transport times with reactive timescales of denitrification in soil indicate that similar to 75\% of the cultivated areas across Europe are potentially vulnerable to nitrate leaching for at least onethird of the year. We find that neglecting the transient nature of transport and reaction timescale results in a great underestimation of the extent of vulnerable regions by almost 50\%. Therefore, future vulnerability and risk assessment studies must account for the transient behaviour of transport and biogeochemical transformation processes.},
  language  = {en}
}
@article{PalmerGregoryBaggeetal.2020,
  author    = {Palmer, Matthew D. and Gregory, Jonathan and Bagge, Meike and Calvert, Daley and Hagedoorn, Jan Marius and Howard, Tom and Klemann, Volker and Lowe, Jason A. and Roberts, Chris and Slangen, Aimee B. A. and Spada, Giorgio},
  title     = {Exploring the drivers of global and local sea-level change over the 21st century and beyond},
  series = {Earth's future},
  volume    = {8},
  journal   = {Earth's future},
  number    = {9},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {2328-4277},
  doi       = {10.1029/2019EF001413},
  pages     = {1 -- 25},
  year      = {2020},
  abstract  = {We present a new set of global and local sea-level projections at example tide gauge locations under the RCP2.6, RCP4.5, and RCP8.5 emissions scenarios. Compared to the CMIP5-based sea-level projections presented in IPCC AR5, we introduce a number of methodological innovations, including (i) more comprehensive treatment of uncertainties, (ii) direct traceability between global and local projections, and (iii) exploratory extended projections to 2300 based on emulation of individual CMIP5 models. Combining the projections with observed tide gauge records, we explore the contribution to total variance that arises from sea-level variability, different emissions scenarios, and model uncertainty. For the period out to 2300 we further breakdown the model uncertainty by sea-level component and consider the dependence on geographic location, time horizon, and emissions scenario. Our analysis highlights the importance of local variability for sea-level change in the coming decades and the potential value of annual-to-decadal predictions of local sea-level change. Projections to 2300 show a substantial degree of committed sea-level rise under all emissions scenarios considered and highlight the reduced future risk associated with RCP2.6 and RCP4.5 compared to RCP8.5. Tide gauge locations can show large ( > 50\%) departures from the global average, in some cases even reversing the sign of the change. While uncertainty in projections of the future Antarctic ice dynamic response tends to dominate post-2100, we see substantial differences in the breakdown of model variance as a function of location, time scale, and emissions scenario.},
  language  = {en}
}
@article{JonesArpGrosseetal.2020,
  author    = {Jones, Benjamin M. and Arp, Christopher D. and Grosse, Guido and Nitze, Ingmar and Lara, Mark J. and Whitman, Matthew S. and Farquharson, Louise M. and Kanevskiy, Mikhail and Parsekian, Andrew D. and Breen, Amy L. and Ohara, Nori and Rangel, Rodrigo Correa and Hinkel, Kenneth M.},
  title     = {Identifying historical and future potential lake drainage events on the western Arctic coastal plain of Alaska},
  series = {Permafrost and Periglacial Processes},
  volume    = {31},
  journal   = {Permafrost and Periglacial Processes},
  number    = {1},
  publisher = {Wiley},
  address   = {New York},
  doi       = {10.1002/ppp.2038},
  pages     = {110 -- 127},
  year      = {2020},
  abstract  = {Arctic lakes located in permafrost regions are susceptible to catastrophic drainage. In this study, we reconstructed historical lake drainage events on the western Arctic Coastal Plain of Alaska between 1955 and 2017 using USGS topographic maps, historical aerial photography (1955), and Landsat Imagery (ca. 1975, ca. 2000, and annually since 2000). We identified 98 lakes larger than 10 ha that partially (>25\% of area) or completely drained during the 62-year period. Decadal-scale lake drainage rates progressively declined from 2.0 lakes/yr (1955-1975), to 1.6 lakes/yr (1975-2000), and to 1.2 lakes/yr (2000-2017) in the ~30,000-km(2) study area. Detailed Landsat trend analysis between 2000 and 2017 identified two years, 2004 and 2006, with a cluster (five or more) of lake drainages probably associated with bank overtopping or headward erosion. To identify future potential lake drainages, we combined the historical lake drainage observations with a geospatial dataset describing lake elevation, hydrologic connectivity, and adjacent lake margin topographic gradients developed with a 5-m-resolution digital surface model. We identified ~1900 lakes likely to be prone to drainage in the future. Of the 20 lakes that drained in the most recent study period, 85\% were identified in this future lake drainage potential dataset. Our assessment of historical lake drainage magnitude, mechanisms and pathways, and identification of potential future lake drainages provides insights into how arctic lowland landscapes may change and evolve in the coming decades to centuries.},
  language  = {en}
}
@article{FosterGarvieWeissetal.2020,
  author    = {Foster, William J. and Garvie, Christopher L. and Weiss, Anna M. and Muscente, A. Drew and Aberhan, Martin and Counts, John W. and Martindale, Rowan C.},
  title     = {Resilience of marine invertebrate communities during the early Cenozoic hyperthermals},
  series = {Scientific Reports},
  volume    = {10},
  journal   = {Scientific Reports},
  number    = {1},
  publisher = {Springer Nature},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/s41598-020-58986-5},
  pages     = {1 -- 11},
  year      = {2020},
  abstract  = {The hyperthermal events of the Cenozoic, including the Paleocene-Eocene Thermal Maximum, provide an opportunity to investigate the potential effects of climate warming on marine ecosystems. Here, we examine the shallow benthic marine communities preserved in the late Cretaceous to Eocene strata on the Gulf Coastal Plain (United States). In stark contrast to the ecological shifts following the end-Cretaceous mass extinction, our data show that the early Cenozoic hyperthermals did not have a long-term impact on the generic diversity nor composition of the Gulf Coastal Plain molluscan communities. We propose that these communities were resilient to climate change because molluscs are better adapted to high temperatures than other taxa, as demonstrated by their physiology and evolutionary history. In terms of resilience, these communities differ from other shallow-water carbonate ecosystems, such as reef communities, which record significant changes during the early Cenozoic hyperthermals. These data highlight the strikingly different responses of community types, i.e., the almost imperceptible response of molluscs versus the marked turnover of foraminifera and reef faunas. The impact on molluscan communities may have been low because detrimental conditions did not devastate the entire Gulf Coastal Plain, allowing molluscs to rapidly recolonise vacated areas once harsh environmental conditions ameliorated.},
  language  = {en}
}
@article{TardifFluteauDonnadieuetal.2020,
  author    = {Tardif, Delphine and Fluteau, Fr{\´e}d{\´e}ric and Donnadieu, Yannick and Le Hir, Guillaume and Ladant, Jean-Baptiste and Sepulchre, Pierre and Licht, Alexis and Poblete, Fernando and Dupont-Nivet, Guillaume},
  title     = {The origin of Asian monsoons},
  series = {Climate of the Past},
  volume    = {16},
  journal   = {Climate of the Past},
  number    = {3},
  publisher = {Copernicus Publications},
  address   = {G{\"o}ttingen},
  issn      = {1814-9332},
  doi       = {10.5194/cp-16-847-2020},
  pages     = {847 -- 865},
  year      = {2020},
  abstract  = {The Cenozoic inception and development of the Asian monsoons remain unclear and have generated much debate, as several hypotheses regarding circulation patterns at work in Asia during the Eocene have been proposed in the few last decades. These include (a) the existence of modern-like monsoons since the early Eocene; (b) that of a weak South Asian monsoon (SAM) and little to no East Asian monsoon (EAM); or (c) a prevalence of the Intertropical Convergence Zone (ITCZ) migrations, also referred to as Indonesian-Australian monsoon (I-AM). As SAM and EAM are supposed to have been triggered or enhanced primarily by Asian palaeogeographic changes, their possible inception in the very dynamic Eocene palaeogeographic context remains an open question, both in the modelling and field-based communities. We investigate here Eocene Asian climate conditions using the IPSL-CM5A2 (Sepulchre et al., 2019) earth system model and revised palaeogeographies. Our Eocene climate simulation yields atmospheric circulation patterns in Asia substantially different from modern conditions. A large high-pressure area is simulated over the Tethys ocean, which generates intense low tropospheric winds blowing southward along the western flank of the proto-Himalayan-Tibetan plateau (HTP) system. This low-level wind system blocks, to latitudes lower than 10 degrees N, the migration of humid and warm air masses coming from the Indian Ocean. This strongly contrasts with the modern SAM, during which equatorial air masses reach a latitude of 20-25 degrees N over India and southeastern China. Another specific feature of our Eocene simulation is the widespread subsidence taking place over northern India in the midtroposphere (around 5000 m), preventing deep convective updraught that would transport water vapour up to the condensation level. Both processes lead to the onset of a broad arid region located over northern India and over the HTP. More humid regions of high seasonality in precipitation encircle this arid area, due to the prevalence of the Intertropical Convergence Zone (ITCZ) migrations (or Indonesian-Australian monsoon, I-AM) rather than monsoons. Although the existence of this central arid region may partly result from the specifics of our simulation (model dependence and palaeogeographic uncertainties) and has yet to be confirmed by proxy records, most of the observational evidence for Eocene monsoons are located in the highly seasonal transition zone between the arid area and the more humid surroundings. We thus suggest that a zonal arid climate prevailed over Asia before the initiation of monsoons that most likely occurred following Eocene palaeogeographic changes. Our results also show that precipitation seasonality should be used with caution to infer the presence of a monsoonal circulation and that the collection of new data in this arid area is of paramount importance to allow the debate to move forward.},
  language  = {en}
}
@article{SchuckSchleicherJanssenetal.2020,
  author    = {Schuck, Bernhard and Schleicher, Anja Maria and Janssen, Christoph and Toy, Virginia G. and Dresen, Georg},
  title     = {Fault zone architecture of a large plate-bounding strike-slip fault},
  series = {Solid Earth},
  volume    = {11},
  journal   = {Solid Earth},
  number    = {1},
  publisher = {Copernicus Publications},
  address   = {G{\"o}ttingen},
  issn      = {1869-9529},
  doi       = {10.5194/se-11-95-2020},
  pages     = {95 -- 124},
  year      = {2020},
  abstract  = {New Zealand's Alpine Fault is a large, platebounding strike-slip fault, which ruptures in large (M-w > 8) earthquakes. We conducted field and laboratory analyses of fault rocks to assess its fault zone architecture. Results reveal that the Alpine Fault Zone has a complex geometry, comprising an anastomosing network of multiple slip planes that have accommodated different amounts of displacement. This contrasts with the previous perception of the Alpine Fault Zone, which assumes a single principal slip zone accommodated all displacement. This interpretation is supported by results of drilling projects and geophysical investigations. Furthermore, observations presented here show that the young, largely unconsolidated sediments that constitute the footwall at shallow depths have a significant influence on fault gouge rheological properties and structure.},
  language  = {en}
}
@article{OlenBookhagenStrecker2020,
  author    = {Olen, Stephanie M. and Bookhagen, Bodo and Strecker, Manfred},
  title     = {Corrigendum to: Olen, Stephanie M.; Bookhagen, Bodo; Strecker, Manfred R. : Role of climate and vegetation density in modulating denudation rates in the Himalaya. - Earth and planetary science letters. - 445 (2016), S. 57 - 67. - doi: https://doi.org/10.1016/j.epsl.2016.03.047},
  series = {Earth and planetary science letters},
  volume    = {540},
  journal   = {Earth and planetary science letters},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0012-821X},
  doi       = {10.1016/j.epsl.2020.116252},
  pages     = {5},
  year      = {2020},
  abstract  = {Vegetation has long been hypothesized to influence the nature and rates of surface processes. We test the possible impact of vegetation and climate on denudation rates at orogen scale by taking advantage of a pronounced along-strike gradient in rainfall and vegetation density in the Himalaya. We combine 12 new 10Be denudation rates from the Sutlej Valley and 123 published denudation rates from fluvially- dominated catchments in the Himalaya with remotely-sensed measures of vegetation density and rainfall metrics, and with tectonic and lithologic constraints. In addition, we perform topographic analyses to assess the contribution of vegetation and climate in modulating denudation rates along strike. We observe variations in denudation rates and the relationship between denudation and topography along strike that are most strongly controlled by local rainfall amount and vegetation density, and cannot be explained by along-strike differences in tectonics or lithology. A W-E along-strike decrease in denudation rate variability positively correlates with the seasonality of vegetation density (R = 0.95, p < 0.05), and negatively correlates with mean vegetation density (R = -0.84, p < 0.05). Vegetation density modulates the topographic response to changing denudation rates, such that the functional relationship between denudation rate and topographic steepness becomes increasingly linear as vegetation density increases. We suggest that while tectonic processes locally control the pattern of denudation rates across strike of the Himalaya (i.e., S-N), along strike of the orogen (i.e., E-W) climate exerts a measurable influence on how denudation rates scatter around long-term, tectonically-controlled erosion, and on the functional relationship between topography and denudation},
  language  = {en}
}
@article{KruegerDahmHannemann2020,
  author    = {Kr{\"u}ger, Frank and Dahm, Torsten and Hannemann, Katrin},
  title     = {Mapping of Eastern North Atlantic Ocean seismicity from Po/So observations at a mid-aperture seismological broad-band deep sea array},
  series = {Geophysical journal international},
  volume    = {221},
  journal   = {Geophysical journal international},
  number    = {2},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0956-540X},
  doi       = {10.1093/gji/ggaa054},
  pages     = {1055 -- 1080},
  year      = {2020},
  abstract  = {A mid-aperture broad-band test array (OBS array DOCTAR) was deployed from June 2011 to April 2012 about 100 km north of the Gloria fault in the Eastern North Atlantic in about 5000 m water depth. In addition arrays were installed on Madeira Island and in western Portugal mainland. For the first time in the Eastern North Atlantic, we recorded a large number of high frequency Po and So waves from local and regional small and moderate earthquakes (M-L < 4). An incoherent beamforming method was adapted to scan continuous data for such Po and So arrivals applying a sliding window waveform migration and frequency-wavenumber technique. We identify about 320 Po and 1550 So arrivals and compare the phase onsets with the ISC catalogue (ISC 2015) for the same time span. Up to a distance of 6 degrees to the DOCTAR stations all events listed in the ISC catalogue could be associated to Po and So phases. Arrivals from events in more than 10 degrees distance could be identified only in some cases. Only few Po and/or So arrivals were detected for earthquakes from the European and African continental area, the continental shelf regions and for earthquakes within or northwest of the Azores plateau. Unexpectedly, earthquake clusters are detected within the oceanic plates north and south of the Gloria fault and far from plate boundaries, indicating active intraplate structures. We also observe and locate numerous small magnitude earthquakes on the segment of the Gloria fault directly south of DOCTAR, which likely coincides with the rupture of the 25 November 1941 event. Local small magnitude earthquakes located beneath DOCTAR show hypocentres up to 30 km depth and strike-slip focal mechanisms. A comparison with detections at temporary mid-aperture arrays on Madeira and in western Portugal shows that the deep ocean array performs much better than the island and the continental array regarding the detection threshold for events in the oceanic plates. We conclude that sparsely distributed mid-aperture seismic arrays in the deep ocean could decrease the detection and location threshold for seismicity with M-L < 4 in the oceanic plate and might constitute a valuable tool to monitor oceanic plate seismicity.},
  language  = {en}
}
@article{GrotheerMeyerRiedeletal.2020,
  author    = {Grotheer, Hendrik and Meyer, Vera and Riedel, Theran and Pfalz, Gregor and Mathieu, Lucie and Hefter, Jens H. and Gentz, Torben and Lantuit, Hugues and Mollennauer, Gesine and Fritz, Michael},
  title     = {Burial and origin of permafrost-derived carbon in the nearshore zone of the southern Canadian Beaufort Sea},
  series = {Geophysical research letters},
  volume    = {47},
  journal   = {Geophysical research letters},
  number    = {3},
  publisher = {Wiley},
  address   = {Hoboken, NJ},
  issn      = {0094-8276},
  doi       = {10.1029/2019GL085897},
  pages     = {11},
  year      = {2020},
  abstract  = {Detailed organic geochemical and carbon isotopic (delta C-13 and Delta C-14) analyses are performed on permafrost deposits affected by coastal erosion (Herschel Island, Canadian Beaufort Sea) and adjacent marine sediments (Herschel Basin) to understand the fate of organic carbon in Arctic nearshore environments. We use an end-member model based on the carbon isotopic composition of bulk organic matter to identify sources of organic carbon. Monte Carlo simulations are applied to quantify the contribution of coastal permafrost erosion to the sedimentary carbon budget. The models suggest that similar to 40\% of all carbon released by local coastal permafrost erosion is efficiently trapped and sequestered in the nearshore zone. This highlights the importance of sedimentary traps in environments such as basins, lagoons, troughs, and canyons for the carbon sequestration in previously poorly investigated, nearshore areas. Plain Language Summary Increasing air and sea surface temperatures at high latitudes leads to accelerated thaw, destabilization, and erosion of perennially frozen soils (i.e., permafrost), which are often rich in organic carbon. Coastal erosion leads to an increased mobilization of organic carbon into the Arctic Ocean, which there can be converted into greenhouse gases and may therefore contribute to further warming. Carbon decomposition can be limited if organic matter is efficiently deposited on the seafloor, buried in marine sediments, and thus removed from the short-term carbon cycle. Basins, canyons, and troughs near the coastline can serve as sediment traps and potentially accommodate large quantities of organic carbon along the Arctic coast. Here we use biomarkers (source-specific molecules), stable carbon isotopes, and radiocarbon to identify the sources of organic carbon in the nearshore zone of the southern Canadian Beaufort Sea near Herschel Island. We quantify the contribution of coastal permafrost erosion to the sedimentary carbon budget of the area and estimate that more than a third of all carbon released by local permafrost erosion is efficiently trapped in marine sediments. This highlights the importance of regional sediment traps for carbon sequestration.},
  language  = {en}
}
@article{PowaliSharmaMandaletal.2020,
  author    = {Powali, Debarchan and Sharma, Shubham and Mandal, Riddhi and Mitra, Supriyo},
  title     = {A reappraisal of the 2005 Kashmir (M-w 7.6) earthquake and its aftershocks},
  series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  volume    = {789},
  journal   = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0040-1951},
  doi       = {10.1016/j.tecto.2020.228501},
  pages     = {11},
  year      = {2020},
  abstract  = {We study the source properties of the 2005 Kashmir earthquake and its aftershocks to unravel the seismotectonics of the NW Himalayan syntaxis. The mainshock and larger aftershocks have been simultaneously relocated using phase data. We use back-projection of high-frequency energy from multiple teleseismic arrays to model the spatio-temporal evolution of the mainshock rupture. Our analysis reveal a bilateral rupture, which initially propagated SE and then NW of the epicenter, with an average rupture velocity of similar to 2 km s(-1). The area of maximum energy release is parallel to and bound by the surface rupture. Incorporating rupture propagation and velocity, we model the mainshock as a line source using P- and SH-waveform inversion. Our result confirms that the mainshock occurred on a NE dipping (similar to 35 degrees) fault plane, with centroid depth of similar to 10 km. Integrated source time function show that majority of the energy was released in the first similar to 20 s, and was confined above the hypocenter. From waveform inverted fault dimension and seismic moment, we argue that the mainshock had an additional similar to 25 km blind rupture beyond the NW Himalayan syntaxis. Combining this with findings from previous studies, we conjecture that the blind rupture propagated NW of the syntaxis underneath a weak detachment overlain by infra-Cambrian salt layer, and terminated in a wedge thrust. All moderate-to-large aftershocks, NW of the mainshock rupture, are concentrated at the edge of the blind rupture termination. Source modeling of these aftershocks reveal thrust mechanism with centroid depths of 2-10 km, and fault planes oriented subparallel to the mainshock rupture. To study the influence of mainshock rupture on aftershock occurrence, we compute Coulomb failure stress on aftershock faults. All these aftershocks lie in the positive Coulomb stress change region. This suggest that the aftershocks have been triggered by either co-seismic or post-seismic slip on the mainshock fault.},
  language  = {en}
}
@article{VolantePourteauCollinsetal.2020,
  author    = {Volante, Silvia and Pourteau, Amaury and Collins, William J. and Blereau, Eleanore and Li, Zheng-Xiang and Smit, Matthijs Arjen and Evans, Noreen and Nordsvan, Adam R. and Spencer, Chris J. and McDonald, Brad J. and Li, Jiangyu and G{\"u}nter, Christina},
  title     = {Multiple P-T-d-t paths reveal the evolution of the final Nuna assembly in northeast Australia},
  series = {Journal of metamorphic geology},
  volume    = {38},
  journal   = {Journal of metamorphic geology},
  number    = {6},
  publisher = {Wiley-Blackwell},
  address   = {Oxford [u.a.]},
  issn      = {0263-4929},
  doi       = {10.1111/jmg.12532},
  pages     = {593 -- 627},
  year      = {2020},
  abstract  = {The final assembly of the Mesoproterozoic supercontinent Nuna was marked by the collision of Laurentia and Australia at 1.60 Ga, which is recorded in the Georgetown Inlier of NE Australia. Here, we decipher the metamorphic evolution of this final Nuna collisional event using petrostructural analysis, major and trace element compositions of key minerals, thermodynamic modelling, and multi-method geochronology. The Georgetown Inlier is characterised by deformed and metamorphosed 1.70-1.62 Ga sedimentary and mafic rocks, which were intruded byc. 1.56 Ga old S-type granites. Garnet Lu-Hf and monazite U-Pb isotopic analyses distinguish two major metamorphic events (M1 atc. 1.60 Ga and M2 atc. 1.55 Ga), which allows at least two composite fabrics to be identified at the regional scale-c. 1.60 Ga S1 (consisting in fabrics S1a and S1b) andc. 1.55 Ga S2 (including fabrics S2a and S2b). Also, three tectono-metamorphic domains are distinguished: (a) the western domain, with S1 defined by low-P(LP) greenschist facies assemblages; (b) the central domain, where S1 fabric is preserved as medium-P(MP) amphibolite facies relicts, and locally as inclusion trails in garnet wrapped by the regionally dominant low-Pamphibolite facies S2 fabric; and (c) the eastern domain dominated by upper amphibolite to granulite facies S2 foliation. In the central domain, 1.60 GaMP-medium-T(MT) metamorphism (M1) developed within the staurolite-garnet stability field, with conditions ranging from 530-550 degrees C at 6-7 kbar (garnet cores) to 620-650 degrees C at 8-9 kbar (garnet rims), and it is associated with S1 fabric. The onset of 1.55 GaLP-high-T(HT) metamorphism (M2) is marked by replacement of staurolite by andalusite (M2a/D2a), which was subsequently pseudomorphed by sillimanite (M2b/D2b) where granite and migmatite are abundant.P-Tconditions ranged from 600 to 680 degrees C and 4-6 kbar for the M2b sillimanite stage. 1.60 Ga garnet relicts within the S2 foliation highlight the progressive obliteration of the S1 fabric by regional S2 in the central zone during peak M2 metamorphism. In the eastern migmatitic complex, partial melting of paragneiss and amphibolite occurred syn- to post-S2, at 730-770 degrees C and 6-8 kbar, and at 750-790 degrees C and 6 kbar, respectively. The pressure-temperature-deformation-time paths reconstructed for the Georgetown Inlier suggest ac. 1.60 Ga M1/D1 event recorded under greenschist facies conditions in the western domain and under medium-Pand medium-Tconditions in the central domain. This event was followed by the regional 1.56-1.54 Ga low-Pand high-Tphase (M2/D2), extensively recorded in the central and eastern domains. Decompression between these two metamorphic events is ascribed to an episode of exhumation. The two-stage evolution supports the previous hypothesis that the Georgetown Inlier preserves continental collisional and subsequent thermal perturbation associated with granite emplacement.},
  language  = {en}
}
@article{HennigStockmannKuehn2020,
  author    = {Hennig, Theresa and Stockmann, Madlen and K{\"u}hn, Michael},
  title     = {Simulation of diffusive uranium transport and sorption processes in the Opalinus Clay},
  series = {Applied geochemistry : journal of the International Association of Geochemistry and Cosmochemistry},
  volume    = {123},
  journal   = {Applied geochemistry : journal of the International Association of Geochemistry and Cosmochemistry},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0883-2927},
  doi       = {10.1016/j.apgeochem.2020.104777},
  pages     = {9},
  year      = {2020},
  abstract  = {Diffusive transport and sorption processes of uranium in the Swiss Opalinus Clay were investigated as a function of partial pressure of carbon dioxide pCO(2), varying mineralogy in the facies and associated changes in porewater composition. Simulations were conducted in one-dimensional diffusion models on the 100 m-scale for a time of one million years using a bottom-up approach based on mechanistic surface complexation models as well as cation exchange to quantify sorption. Speciation calculations have shown, uranium is mainly present as U(VI) and must therefore be considered as mobile for in-situ conditions. Uranium migrated up to 26 m in both, the sandy and the carbonate-rich facies, whereas in the shaly facies 16 m was the maximum. The main species was the anionic complex CaUO2(CO3)(3)(2-) . Hence, anion exclusion was taken into account and further reduced the migration distances by 30 \%. The concentrations of calcium and carbonates reflected by the set pCO(2) determine speciation and activity of uranium and consequently the sorption behaviour. Our simulation results allow for the first time to prioritize on the far-field scale the governing parameters for diffusion and sorption of uranium and hence outline the sensitivity of the system. Sorption processes are controlled in descending priority by the carbonate and calcium concentrations, pH, pe and the clay mineral content. Therefore, the variation in porewater composition resulting from the heterogeneity of the facies in the Opalinus Clay formation needs to be considered in the assessment of uranium migration in the far field of a potential repository.},
  language  = {en}
}
@article{TranterDeLuciaWolfgrammetal.2020,
  author    = {Tranter, Morgan Alan and De Lucia, Marco and Wolfgramm, Markus and K{\"u}hn, Michael},
  title     = {Barite scale formation and injectivity loss models for geothermal systems},
  series = {Water},
  volume    = {12},
  journal   = {Water},
  number    = {11},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2073-4441},
  doi       = {10.3390/w12113078},
  pages     = {24},
  year      = {2020},
  abstract  = {Barite scales in geothermal installations are a highly unwanted effect of circulating deep saline fluids. They build up in the reservoir if supersaturated fluids are re-injected, leading to irreversible loss of injectivity. A model is presented for calculating the total expected barite precipitation. To determine the related injectivity decline over time, the spatial precipitation distribution in the subsurface near the injection well is assessed by modelling barite growth kinetics in a radially diverging Darcy flow domain. Flow and reservoir properties as well as fluid chemistry are chosen to represent reservoirs subject to geothermal exploration located in the North German Basin (NGB) and the Upper Rhine Graben (URG) in Germany. Fluids encountered at similar depths are hotter in the URG, while they are more saline in the NGB. The associated scaling amount normalised to flow rate is similar for both regions. The predicted injectivity decline after 10 years, on the other hand, is far greater for the NGB (64\%) compared to the URG (24\%), due to the temperature- and salinity-dependent precipitation rate. The systems in the NGB are at higher risk. Finally, a lightweight score is developed for approximating the injectivity loss using the Damkohler number, flow rate and total barite scaling potential. This formula can be easily applied to geothermal installations without running complex reactive transport simulations.},
  language  = {en}
}
@article{CastinoBookhagenDelaTorre2020,
  author    = {Castino, Fabiana and Bookhagen, Bodo and De la Torre, Alejandro},
  title     = {Atmospheric dynamics of extreme discharge events from 1979 to 2016 in the southern Central Andes},
  series = {Climate dynamics : observational, theoretical and computational research on the climate system},
  volume    = {55},
  journal   = {Climate dynamics : observational, theoretical and computational research on the climate system},
  number    = {11-12},
  publisher = {Springer},
  address   = {Berlin ; Heidelberg [u.a.]},
  issn      = {0930-7575},
  doi       = {10.1007/s00382-020-05458-1},
  pages     = {3485 -- 3505},
  year      = {2020},
  abstract  = {During the South-American Monsoon season, deep convective systems occur at the eastern flank of the Central Andes leading to heavy rainfall and flooding. We investigate the large- and meso-scale atmospheric dynamics associated with extreme discharge events (> 99.9th percentile) observed in two major river catchments meridionally stretching from humid to semi-arid conditions in the southern Central Andes. Based on daily gauge time series and ERA-Interim reanalysis, we made the following three key observations: (1) for the period 1940-2016 daily discharge exhibits more pronounced variability in the southern, semi-arid than in the northern, humid catchments. This is due to a smaller ratio of discharge magnitudes between intermediate (0.2 year return period) and rare events (20 year return period) in the semi-arid compared to the humid areas; (2) The climatological composites of the 40 largest discharge events showed characteristic atmospheric features of cold surges based on 5-day time-lagged sequences of geopotential height at different levels in the troposphere; (3) A subjective classification revealed that 80\% of the 40 largest discharge events are mainly associated with the north-northeastward migration of frontal systems and 2/3 of these are cold fronts, i.e. cold surges. This work highlights the importance of cold surges and their related atmospheric processes for the generation of heavy rainfall events and floods in the southern Central Andes.},
  language  = {en}
}
@article{RamachandranRupakhetiLawrence2020,
  author    = {Ramachandran, Srikanthan and Rupakheti, Maheswar and Lawrence, Mark},
  title     = {Black carbon dominates the aerosol absorption over the Indo-Gangetic Plain and the Himalayan foothills},
  series = {Environment international : a journal of science, technology, health, monitoring and policy},
  volume    = {142},
  journal   = {Environment international : a journal of science, technology, health, monitoring and policy},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0160-4120},
  doi       = {10.1016/j.envint.2020.105814},
  pages     = {12},
  year      = {2020},
  abstract  = {This study, based on new and high quality in situ observations, quantifies for the first time, the individual contributions of light-absorbing aerosols (black carbon (BC), brown carbon (BrC) and dust) to aerosol absorption over the Indo-Gangetic Plain (IGP) and the Himalayan foothill region, a relatively poorly studied region with several sensitive ecosystems of global importance, as well as highly vulnerable populations. The annual and seasonal average single scattering albedo (SSA) over Kathmandu is the lowest of all the locations. The SSA over Kathmandu is < 0.89 during all seasons, which confirms the dominance of light-absorbing carbonaceous aerosols from local and regional sources over Kathmandu. It is observed here that the SSA decreases with increasing elevation, confirming the dominance of light absorbing carbonaceous aerosols at higher elevations. In contrast, the SSA over the IGP does not exhibit a pronounced spatial variation. BC dominates (>= 75\%) the aerosol absorption over the IGP and the Himalayan foothills throughout the year. Higher BC concentration at elevated locations in the Himalayas leads to lower SSA at elevated locations in the Himalayas. The contribution of dust to aerosol absorption is higher throughout the year over the IGP than over the Himalayan foothills. The aerosol absorption over South Asia is very high, exceeding available observations over East Asia, and also exceeds previous model estimates. This quantification will be valuable as observational constraints to help improve regional simulations of climate change, impacts on the glaciers and the hydrological cycle, and will help to direct the focus towards BC as the main contributor to aerosol-induced warming in the region.},
  language  = {en}
}
@article{DurandBentzKwiateketal.2020,
  author    = {Durand, Virginie and Bentz, Stephan and Kwiatek, Grzegorz and Dresen, Georg and Wollin, Christopher and Heidbach, Oliver and Martinez-Garzon, Patricia and Cotton, Fabrice Pierre and Nurlu, Murat and Bohnhoff, Marco},
  title     = {A two-scale preparation phase preceded an M-w 5.8 earthquake in the sea of marmara offshore Istanbul, Turkey},
  series = {Seismological research letters},
  volume    = {91},
  journal   = {Seismological research letters},
  number    = {6},
  address   = {Boulder},
  issn      = {0895-0695},
  doi       = {10.1785/0220200110},
  pages     = {3139 -- 3147},
  year      = {2020},
  abstract  = {We analyze the spatiotemporal evolution of seismicity during a sequence of moderate (an M-w 4.7 foreshock and M-w 5.8 mainshock) earthquakes occurring in September 2019 at the transition between a creeping and a locked segment of the North Anatolian fault in the central Sea of Marmara, northwest Turkey. To investigate in detail the seismicity evolution, we apply a matched-filter technique to continuous waveforms, thus reducing the magnitude threshold for detection. Sequences of foreshocks preceding the two largest events are clearly seen, exhibiting two different behaviors: a long-term activation of the seismicity along the entire fault segment and a short-term concentration around the epicenters of the large events. We suggest a two-scale preparation phase, with aseismic slip preparing the mainshock final rupture a few days before, and a cascade mechanism leading to the nucleation of the mainshock. Thus, our study shows a combination of seismic and aseismic slip during the foreshock sequence changing the strength of the fault, bringing it closer to failure.},
  language  = {en}
}
@article{ZozulyaKullerudRibackietal.2020,
  author    = {Zozulya, Dmitry R. and Kullerud, Kare and Ribacki, Enrico and Altenberger, Uwe and Sudo, Masafumi and Savchenko, Yevgeny E.},
  title     = {The newly discovered neoproterozoic aillikite occurrence in Vinoren (Southern Norway)},
  series = {Minerals},
  volume    = {10},
  journal   = {Minerals},
  number    = {11},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2075-163X},
  doi       = {10.3390/min10111029},
  pages     = {26},
  year      = {2020},
  abstract  = {During the period 750-600 Ma ago, prior to the final break-up of the supercontinent Rodinia, the crust of both the North American Craton and Baltica was intruded by significant amounts of rift-related magmas originating from the mantle. In the Proterozoic crust of Southern Norway, the 580 Ma old Fen carbonatite-ultramafic complex is a representative of this type of rocks. In this paper, we report the occurrence of an ultramafic lamprophyre dyke which possibly is linked to the Fen complex, although Ar-40/Ar-39 data from phenocrystic phlogopite from the dyke gave an age of 686 +/- 9 Ma. The lamprophyre dyke was recently discovered in one of the Kongsberg silver mines at Vinoren, Norway. Whole rock geochemistry, geochronological and mineralogical data from the ultramafic lamprophyre dyke are presented aiming to elucidate its origin and possible geodynamic setting. From the whole-rock composition of the Vinoren dyke, the rock could be recognized as transitional between carbonatite and kimberlite-II (orangeite). From its diagnostic mineralogy, the rock is classified as aillikite. The compositions and xenocrystic nature of several of the major and accessory minerals from the Vinoren aillikite are characteristic for diamondiferous rocks (kimberlites/lamproites/UML): Phlogopite with kinoshitalite-rich rims, chromite-spinel-ulvospinel series, Mg- and Mn-rich ilmenites, rutile and lucasite-(Ce). We suggest that the aillikite melt formed during partial melting of a MARID (mica-amphibole-rutile-ilmenite-diopside)-like source under CO2 fluxing. The pre-rifting geodynamic setting of the Vinoren aillikite before the Rodinia supercontinent breakup suggests a relatively thick SCLM (Subcontinental Lithospheric Mantle) during this stage and might indicate a diamond-bearing source for the parental melt. This is in contrast to the about 100 Ma younger Fen complex, which were derived from a thin SCLM.},
  language  = {en}
}
@article{vonSpechtCotton2020,
  author    = {von Specht, Sebastian and Cotton, Fabrice Pierre},
  title     = {A link between machine learning and optimization in ground-motion model development},
  series = {Bulletin of the Seismological Society of America},
  volume    = {110},
  journal   = {Bulletin of the Seismological Society of America},
  number    = {6},
  publisher = {Seismological Society of America},
  address   = {Albany},
  issn      = {0037-1106},
  doi       = {10.1785/0120190133},
  pages     = {2777 -- 2800},
  year      = {2020},
  abstract  = {The steady increase of ground-motion data not only allows new possibilities but also comes with new challenges in the development of ground-motion models (GMMs). Data classification techniques (e.g., cluster analysis) do not only produce deterministic classifications but also probabilistic classifications (e.g., probabilities for each datum to belong to a given class or cluster). One challenge is the integration of such continuous classification in regressions for GMM development such as the widely used mixed-effects model. We address this issue by introducing an extension of the mixed-effects model to incorporate data weighting. The parameter estimation of the mixed-effects model, that is, fixed-effects coefficients of the GMMs and the random-effects variances, are based on the weighted likelihood function, which also provides analytic uncertainty estimates. The data weighting permits for earthquake classification beyond the classical, expert-driven, binary classification based, for example, on event depth, distance to trench, style of faulting, and fault dip angle. We apply Angular Classification with Expectation-maximization, an algorithm to identify clusters of nodal planes from focal mechanisms to differentiate between, for example, interface- and intraslab-type events. Classification is continuous, that is, no event belongs completely to one class, which is taken into account in the ground-motion modeling. The theoretical framework described in this article allows for a fully automatic calibration of ground-motion models using large databases with automated classification and processing of earthquake and ground-motion data. As an example, we developed a GMM on the basis of the GMM by Montalva et al. (2017) with data from the strong-motion flat file of Bastias and Montalva (2016) with similar to 2400 records from 319 events in the Chilean subduction zone. Our GMM with the data-driven classification is comparable to the expert-classification-based model. Furthermore, the model shows temporal variations of the between-event residuals before and after large earthquakes in the region.},
  language  = {en}
}
@article{SieberYaxleyHermann2020,
  author    = {Sieber, Melanie Jutta and Yaxley, Gregory M. and Hermann, J{\"o}rg},
  title     = {Investigation of fluid-driven carbonation of a hydrated, forearc mantle wedge using serpentinite cores in high-pressure experiments},
  series = {Journal of petrology},
  volume    = {61},
  journal   = {Journal of petrology},
  number    = {3},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0022-3530},
  doi       = {10.1093/petrology/egaa035},
  pages     = {24},
  year      = {2020},
  abstract  = {High-pressure experiments were performed to investigate the effectiveness, rate and mechanism of carbonation of serpentinites by a carbon-saturated COH fluid at 1.5-2.5 GPa and 375-700 degrees C. This allows a better understanding of the fate and redistribution of slab-derived carbonic fluids when they react with the partially hydrated mantle within and above the subducting slab under pressure and temperature conditions corresponding to the forearc mantle. Interactions between carbon-saturated CO2-H2O-CH4 fluids and serpentinite were investigated using natural serpentinite cylinders with natural grain sizes and shapes in piston-cylinder experiments. The volatile composition of post-run fluids was quantified by gas chromatography. Solid phases were examined by Raman spectroscopy, electron microscopy and laser ablation inductively coupled plasma mass spectrometry. Textures, porosity and phase abundances of recovered rock cores were visualized and quantified by three-dimensional, high-resolution computed tomography. We find that carbonation of serpentinites is efficient at sequestering CO2 from the interacting fluid into newly formed magnesite. Time-series experiments demonstrate that carbonation is completed within similar to 96 h at 2 GPa and 600 degrees C. With decreasing CO2, aq antigorite is replaced first by magnesite + quartz followed by magnesite + talc + chlorite in distinct, metasomatic fronts. Above antigorite stability magnesite + enstatite + talc + chlorite occur additionally. The formation of fluid-permeable reaction zones enhances the reaction rate and efficiency of carbonation. Carbonation probably occurs via an interface-coupled replacement process, whereby interconnected porosity is present within reaction zones after the experiment. Consequently, carbonation of serpentinites is self-promoting and efficient even if fluid flow is channelized into veins. We conclude that significant amounts of carbonates may accumulate, over time, in the hydrated forearc mantle.},
  language  = {en}
}
@article{CalitriSommervanderMeijetal.2020,
  author    = {Calitri, Francesca and Sommer, Michael and van der Meij, Marijn W. and Egli, Markus},
  title     = {Soil erosion along a transect in a forested catchment: recent or ancient processes?},
  series = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution},
  volume    = {194},
  journal   = {Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0341-8162},
  doi       = {10.1016/j.catena.2020.104683},
  pages     = {11},
  year      = {2020},
  abstract  = {Forested areas are assumed not to be influenced by erosion processes. However, forest soils of Northern Germany in a hummocky ground moraine landscape can sometimes exhibit a very shallow thickness on crest positions and buried soils on slope positions. The question consequently is: Are these on-going or ancient erosional and depositional processes? Plutonium isotopes act as soil erosion/deposition tracers for recent (last few decades) processes. Here, we quantified the 239+240PU inventories in a small, forested catchment (ancient forest "Melzower Forst", deciduous trees), which is characterised by a hummocky terrain including a kettle hole. Soil development depths (depth to C horizon) and 239+240PU inventories along a catena of sixteen different profiles were determined and correlated to relief parameters. Moreover, we compared different modelling approaches to derive erosion rates from Pu data. <br /> We find a strong relationship between soil development depths, distance-to-sink and topography along the catena. Fully developed Retisols (thicknesses > 1 m) in the colluvium overlay old land surfaces as documented by fossil Ah horizons. However, we found no relationship of Pu-based erosion rates to any relief parameter. Instead, 239+240PU inventories showed a very high local, spatial variability (36-70 Bq m(-2)). Low annual rainfall, spatially distributed interception and stem flow might explain the high variability of the 239+240PU inventories, giving rise to a patchy input pattern. Different models resulted in quite similar erosion and deposition rates (max: -5 t ha(-1) yr(-1) to +7.3 t ha(-1) yr(-1)). Although some rates are rather high, the magnitude of soil erosion and deposition - in terms of soil thickness change - is negligible during the last 55 years. The partially high values are an effect of the patchy Pu deposition on the forest floor. This forest has been protected for at least 240 years. Therefore rather natural events and anthropogenic activities during medieval times or even earlier must have caused the observed soil pattern, which documents strong erosion and deposition processes.},
  language  = {en}
}
@article{ZhangChenKuangetal.2020,
  author    = {Zhang, Liyu and Chen, Daizhao and Kuang, Guodun and Guo, Zenghui and Zhang, Gongjing and Wang, Xia},
  title     = {Persistent oxic deep ocean conditions and frequent volcanic activities during the Frasnian-Famennian transition recorded in South China},
  series = {Global and planetary change},
  volume    = {195},
  journal   = {Global and planetary change},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0921-8181},
  doi       = {10.1016/j.gloplacha.2020.103350},
  pages     = {11},
  year      = {2020},
  abstract  = {The Frasnian-Famennian (F-F) transition of Late Devonian was a critical episode in geological history, recording a major mass extinction event. In this study, we focus on an F-F succession from a deep marine context in Bancheng, southern Guangxi, South China, to investigate coeval changes in pelagic environments of the Paleo-Tethys Ocean. The studied succession is exclusively composed of bedded cherts intercalated with multiple siliceous volcanic ash beds. A SIMS zircon U-Pb Concordia age of 367.8 +/- 2.5 Ma is reported for a tuffaceous layer slightly above the F-F boundary. Geochemical ratios of Al/(Al + Fe + Mn), Ce/Ce*, Y/Ho, and Al, Fe contents in bedded cherts indicate that they are of predominantly biogenic/chemical origin with some terrigenous inputs. Negligible enrichment of redox sensitive elements (Mo, U, V) and low V/Cr ratios (<2) suggest persistently oxic conditions existed in the deep pelagic basin at Bancheng, South China during the F-F transition. These findings call into question the widely held hypothesis that marine anoxia was the primary killing mechanism for the F-F crisis. In contrast, multiple tuffaceous layers throughout the F-F boundary succession indicate frequent volcanic activity, which could have released massive amounts of greenhouse gases into the atmosphere, inducing climate warming. This scenario may have increased continental weathering and riverine fluxes into the ocean, reconciling the increases in Al2O3 content and Al/(Al + Fe + Mn) ratio across the F-F boundary. Documentation of persistently oxic conditions and frequent volcanic activitiy provides new perspectives on the inter-relationship between volcanism, climate, and oceanic redox fluctuation during the F-F biotic crisis.},
  language  = {en}
}
@article{BrillPassuniPinedaEspichanCuyaetal.2020,
  author    = {Brill, Fabio Alexander and Passuni Pineda, Silvia and Espichan Cuya, Bruno and Kreibich, Heidi},
  title     = {A data-mining approach towards damage modelling for El Nino events in Peru},
  series = {Geomatics, natural hazards and risk},
  volume    = {11},
  journal   = {Geomatics, natural hazards and risk},
  number    = {1},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {1947-5705},
  doi       = {10.1080/19475705.2020.1818636},
  pages     = {1966 -- 1990},
  year      = {2020},
  abstract  = {Compound natural hazards likeEl Ninoevents cause high damage to society, which to manage requires reliable risk assessments. Damage modelling is a prerequisite for quantitative risk estimations, yet many procedures still rely on expert knowledge, and empirical studies investigating damage from compound natural hazards hardly exist. A nationwide building survey in Peru after theEl Ninoevent 2017 - which caused intense rainfall, ponding water, flash floods and landslides - enables us to apply data-mining methods for statistical groundwork, using explanatory features generated from remote sensing products and open data. We separate regions of different dominant characteristics through unsupervised clustering, and investigate feature importance rankings for classifying damage via supervised machine learning. Besides the expected effect of precipitation, the classification algorithms select the topographic wetness index as most important feature, especially in low elevation areas. The slope length and steepness factor ranks high for mountains and canyons. Partial dependence plots further hint at amplified vulnerability in rural areas. An example of an empirical damage probability map, developed with a random forest model, is provided to demonstrate the technical feasibility.},
  language  = {en}
}
@article{WietzkeMerzGerlitzetal.2020,
  author    = {Wietzke, Luzie M. and Merz, Bruno and Gerlitz, Lars and Kreibich, Heidi and Guse, Bj{\"o}rn and Castellarin, Attilio and Vorogushyn, Sergiy},
  title     = {Comparative analysis of scalar upper tail indicators},
  series = {Hydrological sciences journal = Journal des sciences hydrologiques},
  volume    = {65},
  journal   = {Hydrological sciences journal = Journal des sciences hydrologiques},
  number    = {10},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {0262-6667},
  doi       = {10.1080/02626667.2020.1769104},
  pages     = {1625 -- 1639},
  year      = {2020},
  abstract  = {Different upper tail indicators exist to characterize heavy tail phenomena, but no comparative study has been carried out so far. We evaluate the shape parameter (GEV), obesity index, Gini index and upper tail ratio (UTR) against a novel benchmark of tail heaviness - the surprise factor. Sensitivity analyses to sample size and changes in scale-to-location ratio are carried out in bootstrap experiments. The UTR replicates the surprise factor best but is most uncertain and only comparable between records of similar length. For samples with symmetric Lorenz curves, shape parameter, obesity and Gini indices provide consistent indications. For asymmetric Lorenz curves, however, the first two tend to overestimate, whereas Gini index tends to underestimate tail heaviness. We suggest the use of a combination of shape parameter, obesity and Gini index to characterize tail heaviness. These indicators should be supported with calculation of the Lorenz asymmetry coefficients and interpreted with caution.},
  language  = {en}
}
@article{KruseKolmogorovPestryakovaetal.2020,
  author    = {Kruse, Stefan and Kolmogorov, Aleksey I. and Pestryakova, Luidmila Agafyevna and Herzschuh, Ulrike},
  title     = {Long-lived larch clones may conserve adaptations that could restrict treeline migration in northern Siberia},
  series = {Ecology and evolution},
  volume    = {10},
  journal   = {Ecology and evolution},
  number    = {18},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {2045-7758},
  doi       = {10.1002/ece3.6660},
  pages     = {10017 -- 10030},
  year      = {2020},
  abstract  = {The occurrence of refugia beyond the arctic treeline and genetic adaptation therein play a crucial role of largely unknown effect size. While refugia have potential for rapidly colonizing the tundra under global warming, the taxa may be maladapted to the new environmental conditions. Understanding the genetic composition and age of refugia is thus crucial for predicting any migration response. Here, we genotype 194 larch individuals from an similar to 1.8 km(2)area in northcentral Siberia on the southern Taimyr Peninsula by applying an assay of 16 nuclear microsatellite markers. For estimating the age of clonal individuals, we counted tree rings at sections along branches to establish a lateral growth rate that was then combined with geographic distance. Findings reveal that the predominant reproduction type is clonal (58.76\%) by short distance spreading of ramets. One outlier of clones 1 km apart could have been dispersed by reindeer. In clonal groups and within individuals, we find that somatic mutations accumulate with geographic distance. Clonal groups of two or more individuals are observed. Clonal age estimates regularly suggest individuals as old as 2,200 years, which coincides with a major environmental change that forced a treeline retreat in the region. We conclude that individuals with clonal growth mode were naturally selected as it lowers the likely risk of extinction under a harsh environment. We discuss this legacy from the past that might now be a maladaptation and hinder expansion under currently strongly increasing temperatures.},
  language  = {en}
}
@article{VossBookhagenSachseetal.2020,
  author    = {Voss, Katalyn A. and Bookhagen, Bodo and Sachse, Dirk and Chadwick, Oliver A.},
  title     = {Variation of deuterium excess in surface waters across a 5000-m elevation gradient in eastern Nepal},
  series = {Journal of hydrology},
  volume    = {586},
  journal   = {Journal of hydrology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0022-1694},
  doi       = {10.1016/j.jhydrol.2020.124802},
  pages     = {17},
  year      = {2020},
  abstract  = {The strong elevation gradient of the Himalaya allows for investigation of altitude and orographic impacts on surface water delta O-18 and delta D stable isotope values. This study differentiates the time- and altitude-variable contributions of source waters to the Arun River in eastern Nepal. It provides isotope data along a 5000-m gradient collected from tributaries as well as groundwater, snow, and glacial-sourced surface waters and time-series data from April to October 2016. We find nonlinear trends in delta O-18 and delta D lapse rates with high-elevation lapse rates (4000-6000 masl) 5-7 times more negative than low-elevation lapse rates (1000-3000 masl). A distinct seasonal signal in delta O-18 and delta D lapse rates indicates time-variable source-water contributions from glacial and snow meltwater as well as precipitation transitions between the Indian Summer Monsoon and Winter Westerly Disturbances. Deuterium excess correlates with the extent of snowpack and tracks melt events during the Indian Summer Monsoon season. Our analysis identifies the influence of snow and glacial melt waters on river composition during low-flow conditions before the monsoon (April/May 2016) followed by a 5-week transition to the Indian Summer Monsoon-sourced rainfall around mid-June 2016. In the post-monsoon season, we find continued influence from glacial melt waters as well as ISM-sourced groundwater.},
  language  = {en}
}
@article{GanguliPaprotnyHasanetal.2020,
  author    = {Ganguli, Poulomi and Paprotny, Dominik and Hasan, Mehedi and G{\"u}ntner, Andreas and Merz, Bruno},
  title     = {Projected changes in compound flood hazard from riverine and coastal floods in northwestern Europe},
  series = {Earth's future},
  volume    = {8},
  journal   = {Earth's future},
  number    = {11},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken, NJ},
  issn      = {2328-4277},
  doi       = {10.1029/2020EF001752},
  pages     = {19},
  year      = {2020},
  abstract  = {Compound flooding in coastal regions, that is, the simultaneous or successive occurrence of high sea levels and high river flows, is expected to increase in a warmer world. To date, however, there is no robust evidence on projected changes in compound flooding for northwestern Europe. We combine projected storm surges and river floods with probabilistic, localized relative sea-level rise (SLR) scenarios to assess the future compound flood hazard over northwestern coastal Europe in the high (RCP8.5) emission scenario. We use high-resolution, dynamically downscaled regional climate models (RCM) to drive a storm surge model and a hydrological model, and analyze the joint occurrence of high coastal water levels and associated river peaks in a multivariate copula-based approach. The RCM-forced multimodel mean reasonably represents the observed spatial pattern of the dependence strength between annual maxima surge and peak river discharge, although substantial discrepancies exist between observed and simulated dependence strength. All models overestimate the dependence strength, possibly due to limitations in model parameterizations. This bias affects compound flood hazard estimates and requires further investigation. While our results suggest decreasing compound flood hazard over the majority of sites by 2050s (2040-2069) compared to the reference period (1985-2005), an increase in projected compound flood hazard is limited to around 34\% of the sites. Further, we show the substantial role of SLR, a driver of compound floods, which has frequently been neglected. Our findings highlight the need to be aware of the limitations of the current generation of Earth system models in simulating coastal compound floods.},
  language  = {en}
}
@article{VogtVincentLippoldKabothBahretal.2020,
  author    = {Vogt-Vincent, Noam and Lippold, J{\"o}rg and Kaboth-Bahr, Stefanie and Blaser, Patrick},
  title     = {Ice-rafted debris as a source of non-conservative behaviour for the epsilon Nd palaeotracer},
  series = {Geo-marine letters : an international journal of marine geology},
  volume    = {40},
  journal   = {Geo-marine letters : an international journal of marine geology},
  number    = {3},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {0276-0460},
  doi       = {10.1007/s00367-020-00643-x},
  pages     = {325 -- 340},
  year      = {2020},
  abstract  = {Neodymium isotopic composition (epsilon Nd) has enjoyed widespread use as a palaeotracer, principally because it behaves quasi-conservatively in the modern ocean. However, recent bottom water epsilon Nd reconstructions from the eastern North Atlantic are difficult to interpret under assumptions of conservative behaviour. The observation that this apparent departure from conservative behaviour increases with enhanced ice-rafted debris (IRD) fluxes has resulted in the suggestion that IRD leads to the overprinting of bottom water epsilon Nd through reversible scavenging. In this study, a simple water column model successfully reproduces epsilon Nd reconstructions from the eastern North Atlantic at the Last Glacial Maximum and Heinrich Stadial 1, and demonstrates that the changes in scavenging intensity required for good model-data fit is in good agreement with changes in the observed IRD flux. Although uncertainties in model parameters preclude a more definitive conclusion, the results indicate that the suggestion of IRD as a source of non-conservative behaviour in the epsilon Nd tracer is reasonable and that further research into the fundamental chemistry underlying the marine neodymium cycle is necessary to increase confidence in assumptions of conservative epsilon Nd behaviour in the past.},
  language  = {en}
}
@article{HuangHerzschuhPestryakovaetal.2020,
  author    = {Huang, Sichao and Herzschuh, Ulrike and Pestryakova, Luidmila Agafyevna and Zimmermann, Heike Hildegard and Davydova, Paraskovya and Biskaborn, Boris and Shevtsova, Iuliia and Stoof-Leichsenring, Kathleen Rosemarie},
  title     = {Genetic and morphologic determination of diatom community composition in surface sediments from glacial and thermokarst lakes in the Siberian Arctic},
  series = {Journal of paleolimnolog},
  volume    = {64},
  journal   = {Journal of paleolimnolog},
  number    = {3},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {0921-2728},
  doi       = {10.1007/s10933-020-00133-1},
  pages     = {225 -- 242},
  year      = {2020},
  abstract  = {Lakes cover large parts of the climatically sensitive Arctic landscape and respond rapidly to environmental change. Arctic lakes have different origins and include the predominant thermokarst lakes, which are small, young and highly dynamic, as well as large, old and stable glacial lakes. Freshwater diatoms dominate the primary producer community in these lakes and can be used to detect biotic responses to climate and environmental change. We used specific diatom metabarcoding on sedimentary DNA, combined with next-generation sequencing and diatom morphology, to assess diatom diversity in five glacial and 15 thermokarst lakes within the easternmost expanse of the Siberian treeline ecotone in Chukotka, Russia. We obtained 163 verified diatom sequence types and identified 176 diatom species morphologically. Although there were large differences in taxonomic assignment using the two approaches, they showed similar high abundances and diversity of Fragilariceae and Aulacoseiraceae. In particular, the genetic approach detected hidden within-lake variations of fragilarioids in glacial lakes and dominance of centric Aulacoseira species, whereas Lindavia ocellata was predominant using morphology. In thermokarst lakes, sequence types and valve counts also detected high diversity of Fragilariaceae, which followed the vegetation gradient along the treeline. Ordination analyses of the genetic data from glacial and thermokarst lakes suggest that concentrations of sulfate (SO42-), an indicator of the activity of sulfate-reducing microbes under anoxic conditions, and bicarbonate (HCO3-), which relates to surrounding vegetation, have a significant influence on diatom community composition. For thermokarst lakes, we also identified lake depth as an important variable, but SO42- best explains diatom diversity derived from genetic data, whereas HCO3- best explains the data from valve counts. Higher diatom diversity was detected in glacial lakes, most likely related to greater lake age and different edaphic settings, which gave rise to diversification and endemism. In contrast, small, dynamic thermokarst lakes are inhabited by stress-tolerant fragilarioids and are related to different vegetation types along the treeline ecotone. Our study demonstrated that genetic investigations of lake sediments can be used to interpret climate and environmental responses of diatoms. It also showed how lake type affects diatom diversity, and that such genetic analyses can be used to track diatom community changes under ongoing warming in the Arctic.},
  language  = {en}
}
@article{GuzmanSamprognaMohorMendiondo2020,
  author    = {Guzman, Diego A. and Samprogna Mohor, Guilherme and Mendiondo, Eduardo Mario},
  title     = {Multi-year index-based insurance for adapting Water Utility Companies to hydrological drought},
  series = {Water},
  volume    = {12},
  journal   = {Water},
  number    = {11},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2073-4441},
  doi       = {10.3390/w12112954},
  pages     = {22},
  year      = {2020},
  abstract  = {The sustainability of water utility companies is threatened by non-stationary drivers, such as climate and anthropogenic changes. To cope with potential economic losses, instruments such as insurance are useful for planning scenarios and mitigating impacts, but data limitations and risk uncertainties affect premium estimation and, consequently, business sustainability. This research estimated the possible economic impacts of business interruption to the Sao Paulo Water Utility Company derived from hydrological drought and how this could be mitigated with an insurance scheme. Multi-year insurance (MYI) was proposed through a set of "change" drivers: the climate driver, through forcing the water evaluation and planning system (WEAP) hydrological tool; the anthropogenic driver, through water demand projections; and the economic driver, associated with recent water price policies adopted by the utility company during water scarcity periods. In our study case, the evaluated indices showed that MYI contracts that cover only longer droughts, regardless of the magnitude, offer better financial performance than contracts that cover all events (in terms of drought duration). Moreover, through MYI contracts, we demonstrate solvency for the insurance fund in the long term and an annual average actuarially fair premium close to the total expected revenue reduction.},
  language  = {en}
}
@article{IzgiEkenGaebleretal.2020,
  author    = {Izgi, Gizem and Eken, Tuna and Gaebler, Peter and Eulenfeld, Tom and Taymaz, Tuncay},
  title     = {Crustal seismic attenuation parameters in the western region of the North Anatolian Fault Zone},
  series = {Journal of geodynamics},
  volume    = {134},
  journal   = {Journal of geodynamics},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0264-3707},
  doi       = {10.1016/j.jog.2020.101694},
  pages     = {10},
  year      = {2020},
  abstract  = {Detailed knowledge of the crustal structure along the North Anatolian Fault Zone can help in understanding past and present tectonic processes in relation to the deformation history. To estimate the frequency-dependent crustal attenuation parameters beneath the western part of the North Anatolian Fault Zone we apply acoustic radiative transfer theory under the assumption of multiple isotropic scattering to generate synthetic seismogram envelopes. The inversion depends on finding an optimal fit between observed and synthetically computed coda wave envelopes in five frequency bands. 2-D lateral variation of intrinsic and scattering attenuation at various frequencies tends to three crustal blocks (i.e., Armutlu-Almacik, Istanbul-Zonguldak and Sakarya Zones) separated by the southern and northern branches of the western part of the North Anatolian Fault Zone. Overall, scattering attenuation appears to be dominant over intrinsic attenuation in the study area at lower frequencies. Relatively low attenuation properties are observed beneath the older Istanbul Zone whereas higher attenuation properties are found for the younger Sakarya Zone. The Armutlu Almacik Zone exhibits more complex lateral variations. Very high attenuation values towards the west characterize the area of the Kuzuluk Basin, a pull-apart basin formed under west-east extension. Our coda-derived moment magnitudes are similar to the local magnitude estimates that were previously calculated for the same earthquakes. For smaller earthquakes (M-L < 2.5), however, the relation between local and moment magnitudes appears to lose its coherency. This may stem from various reasons including the use of seismic data recorded in finite sampling interval, possible biases in local magnitude estimates of earthquake catalogues as well as biases due to wrong assumptions to consider anelastic attenuation terms.},
  language  = {en}
}
@article{ReschkeKroenerLaepple2020,
  author    = {Reschke, Maria and Kr{\"o}ner, Igor and Laepple, Thomas},
  title     = {Testing the consistency of Holocene and Last Glacial Maximum spatial correlations in temperature proxy records},
  series = {Journal of quaternary science : JQS},
  volume    = {36},
  journal   = {Journal of quaternary science : JQS},
  number    = {1},
  publisher = {Wiley},
  address   = {New York},
  issn      = {0267-8179},
  doi       = {10.1002/jqs.3245},
  pages     = {20 -- 28},
  year      = {2020},
  abstract  = {Holocene temperature proxy records are commonly used in quantitative synthesis and model-data comparisons. However, comparing correlations between time series from records collected in proximity to one another with the expected correlations based on climate model simulations indicates either regional or noisy climate signals in Holocene temperature proxy records. In this study, we evaluate the consistency of spatial correlations present in Holocene proxy records with those found in data from the Last Glacial Maximum (LGM). Specifically, we predict correlations expected in LGM proxy records if the only difference to Holocene correlations would be due to more time uncertainty and more climate variability in the LGM. We compare this simple prediction to the actual correlation structure in the LGM proxy records. We found that time series data of ice-core stable isotope records and planktonic foraminifera Mg/Ca ratios were consistent between the Holocene and LGM periods, while time series of Uk'37 proxy records were not as we found no correlation between nearby LGM records. Our results support the finding of highly regional or noisy marine proxy records in the compilation analysed here and suggest the need for further studies on the role of climate proxies and the processes of climate signal recording and preservation.},
  language  = {en}
}
@article{ZimmermannStoofLeichsenringKruseetal.2020,
  author    = {Zimmermann, Heike Hildegard and Stoof-Leichsenring, Kathleen Rosemarie and Kruse, Stefan and M{\"u}ller, Juliane and Stein, Ruediger and Tiedemann, Ralf and Herzschuh, Ulrike},
  title     = {Changes in the composition of marine and sea-ice diatoms derived from sedimentary ancient DNA of the eastern Fram Strait over the past 30 000 years},
  series = {Ocean science},
  volume    = {16},
  journal   = {Ocean science},
  number    = {5},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1812-0784},
  doi       = {10.5194/os-16-1017-2020},
  pages     = {1017 -- 1032},
  year      = {2020},
  abstract  = {The Fram Strait is an area with a relatively low and irregular distribution of diatom microfossils in surface sediments, and thus microfossil records are scarce, rarely exceed the Holocene, and contain sparse information about past richness and taxonomic composition. These attributes make the Fram Strait an ideal study site to test the utility of sedimentary ancient DNA (sedaDNA) metabarcoding. Amplifying a short, partial rbcL marker from samples of sediment core MSM05/5-712-2 resulted in 95.7\% of our sequences being assigned to diatoms across 18 different families, with 38.6\% of them being resolved to species and 25.8\% to genus level. Independent replicates show a high similarity of PCR products, especially in the oldest samples. Diatom sedaDNA richness is highest in the Late Weichselian and lowest in Mid- and Late Holocene samples. Taxonomic composition is dominated by cold-water and sea-ice-associated diatoms and suggests several reorganisations - after the Last Glacial Maximum, after the Younger Dryas, and after the Early and after the Mid-Holocene. Different sequences assigned to, amongst others, Chaetoceros socialis indicate the detectability of intra-specific diversity using sedaDNA. We detect no clear pattern between our diatom sedaDNA record and the previously published IP25 record of this core, although proportions of pennate diatoms increase with higher IP25 concentrations and proportions of Nitzschia cf. frigida exceeding 2\% of the assemblage point towards past sea-ice presence.},
  language  = {en}
}
@article{MonteroLopezHongnLopezSteinmetzetal.2020,
  author    = {Montero-Lopez, Carolina and Hongn, Fernando D. and Lopez Steinmetz, Romina L. and Aramayo, Alejandro and Pingel, Heiko and Strecker, Manfred and Cottle, John and Bianchi, Carlos},
  title     = {Development of an incipient Paleogene topography between the present-day Eastern Andean Plateau (Puna) and the Eastern Cordillera, southern Central Andes, NW Argentina},
  series = {Basin research / publ. in conjunction with the European Association of Geoscientists \& Engineers and the International Association of Sedimentologists},
  volume    = {33},
  journal   = {Basin research / publ. in conjunction with the European Association of Geoscientists \& Engineers and the International Association of Sedimentologists},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Oxford},
  issn      = {0950-091X},
  doi       = {10.1111/bre.12510},
  pages     = {1194 -- 1217},
  year      = {2020},
  abstract  = {The structural and topographic evolution of orogenic plateaus is an important research topic because of its impact on atmospheric circulation patterns, the amount and distribution of rainfall, and resulting changes in surface processes. The Puna region in the north-western Argentina (between 13 degrees S and 27 degrees S) is part of the Andean Plateau, which is the world's second largest orogenic plateau. In order to investigate the deformational events responsible for the initial growth of this part of the Andean plateau, we carried out structural and stratigraphic investigations within the present-day transition zone between the northern Puna and the adjacent Eastern Cordillera to the east. This transition zone is characterized by ubiquitous exposures of continental middle Eocene redbeds of the Casa Grande Formation. Our structural mapping, together with a sedimentological analysis of these units and their relationships with the adjacent mountain ranges, has revealed growth structures and unconformities that are indicative of syntectonic deposition. These findings support the notion that tectonic shortening in this part of the Central Andes was already active during the middle Paleogene, and that early Cenozoic deformation in the region that now constitutes the Puna occurred in a spatially irregular manner. The patterns of Paleogene deformation and uplift along the eastern margin of the present-day plateau correspond to an approximately north-south oriented swath of reactivated basement heterogeneities (i.e. zones of mechanical weakness) stemming from regional Paleozoic mountain building that may have led to local concentration of deformation belts.},
  language  = {en}
}
@article{ZhouAitchisonLokhoetal.2020,
  author    = {Zhou, Renjie and Aitchison, Jonathan C. and Lokho, Kapesa and Sobel, Edward and Feng, Yuexing and Zhao, Jian-xin},
  title     = {Unroofing the Ladakh Batholith: constraints from autochthonous molasse of the Indus Basin, NW Himalaya},
  series = {Journal of the Geological Society},
  volume    = {177},
  journal   = {Journal of the Geological Society},
  number    = {4},
  publisher = {Geological Society (London)},
  address   = {London},
  issn      = {0016-7649},
  doi       = {10.1144/jgs2019-188},
  pages     = {818 -- 825},
  year      = {2020},
  abstract  = {The Indus Molasse records orogenic sedimentation associated with uplift and erosion of the southern margin of Asia in the course of ongoing India-Eurasia collision. Detailed field investigation clarifies the nature and extent of the depositional contact between this molasse and the underlying basement units. We report the first dataset on detrital zircon U-Pb ages, Hf isotopes and apatite U-Pb ages for the autochthonous molasse in the Indus Suture Zone. A latest Oligocene depositional age is proposed on the basis of the youngest detrital zircon U-Pb age peak and is consistent with published biostratigraphic data. Multiple provenance indicators suggest exclusively northerly derivation with no input from India in the lowermost parts of the section. The results provide constraints on the uplift and erosion history of the Ladakh Range following the initial India-Asia collision.},
  language  = {en}
}
@article{BahrKolberKabothBahretal.2020,
  author    = {Bahr, Andr{\´e} and Kolber, Gilles and Kaboth-Bahr, Stefanie and Reinhardt, Lutz and Friedrich, Oliver and Pross, J{\"o}rg},
  title     = {Mega-monsoon variability during the late Triassic},
  series = {Sedimentology : the journal of the International Association of Sedimentologists},
  volume    = {67},
  journal   = {Sedimentology : the journal of the International Association of Sedimentologists},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Oxford},
  issn      = {0037-0746},
  doi       = {10.1111/sed.12668},
  pages     = {951 -- 970},
  year      = {2020},
  abstract  = {The formation of the supercontinent Pangaea during the Permo-Triassic gave rise to an extreme monsoonal climate (often termed 'mega-monsoon') that has been documented by numerous palaeo-records. However, considerable debate exists about the role of orbital forcing in causing humid intervals in an otherwise arid climate. To shed new light on the forcing of monsoonal variability in subtropical Pangaea, this study focuses on sediment facies and colour variability of playa and alluvial fan deposits in an outcrop from the late Carnian (ca 225 Ma) in the southern Germanic Basin, south-western Germany. The sediments were deposited against a background of increasingly arid conditions following the humid Carnian Pluvial Event (ca 234 to 232 Ma). The ca 2 center dot 4 Myr long sedimentary succession studied shows a tripartite long-term evolution, starting with a distal mud-flat facies deposited under arid conditions. This phase was followed by a highly variable playa-lake environment that documents more humid conditions and finally a regression of the playa-lake due to a return of arid conditions. The red-green (a*) and lightness (L*) records show that this long-term variability was overprinted by alternating wet/dry cycles driven by orbital precession and ca 405 kyr eccentricity, without significant influence of obliquity. The absence of obliquity in this record indicates that high-latitude forcing played only a minor role in the southern Germanic Basin during the late Carnian. This is different from the subsequent Norian when high-latitude signals became more pronounced, potentially related to the northward drift of the Germanic Basin. The recurring pattern of pluvial events during the late Triassic demonstrates that orbital forcing, in particular eccentricity, stimulated the occurrence and intensity of wet phases. It also highlights the possibility that the Carnian Pluvial Event, although most likely triggered by enhanced volcanic activity, may also have been modified by an orbital stimulus.},
  language  = {en}
}
@article{GlerumBruneStampsetal.2020,
  author    = {Glerum, Anne and Brune, Sascha and Stamps, D. Sarah and Strecker, Manfred},
  title     = {Victoria continental microplate dynamics controlled by the lithospheric strength distribution of the East African Rift},
  series = {Nature Communications},
  volume    = {11},
  journal   = {Nature Communications},
  number    = {1},
  publisher = {Nature Publishing Group},
  address   = {London},
  issn      = {2041-1723},
  doi       = {10.1038/s41467-020-16176-x},
  pages     = {15},
  year      = {2020},
  abstract  = {The Victoria microplate between the Eastern and Western Branches of the East African Rift System is one of the largest continental microplates on Earth. In striking contrast to its neighboring plates, Victoria rotates counterclockwise with respect to Nubia. The underlying cause of this distinctive rotation has remained elusive so far. Using 3D numerical models, we investigate the role of pre-existing lithospheric heterogeneities in continental microplate rotation. We find that Victoria's rotation is primarily controlled by the distribution of rheologically stronger zones that transmit the drag of the major plates to the microplate and of the mechanically weaker mobile belts surrounding Victoria that facilitate rotation. Our models reproduce Victoria's GPS-derived counterclockwise rotation as well as key complexities of the regional tectonic stress field. These results reconcile competing ideas on the opening of the rift system by highlighting differences in orientation of the far-field divergence, local extension, and the minimum horizontal stress. One of the largest continental microplates on Earth is situated in the center of the East African Rift System, and oddly, the Victoria microplate rotates counterclockwise with respect to the neighboring African tectonic plate. Here, the authors' modelling results suggest that Victoria microplate rotation is caused by edge-driven lithospheric processes related to the specific geometry of rheologically weak and strong regions.},
  language  = {en}
}
@article{BentzKwiatekMartinezGarzonetal.2020,
  author    = {Bentz, Stephan and Kwiatek, Grzegorz and Martinez-Garzon, Patricia and Bohnhoff, Marco and Dresen, Georg},
  title     = {Seismic moment evolution during hydraulic stimulations},
  series = {Geophysical research letters},
  volume    = {47},
  journal   = {Geophysical research letters},
  number    = {5},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0094-8276},
  doi       = {10.1029/2019GL086185},
  pages     = {9},
  year      = {2020},
  abstract  = {Analysis of past and present stimulation projects reveals that the temporal evolution and growth of maximum observed moment magnitudes may be linked directly to the injected fluid volume and hydraulic energy. Overall evolution of seismic moment seems independent of the tectonic stress regime and is most likely governed by reservoir specific parameters, such as the preexisting structural inventory. Data suggest that magnitudes can grow either in a stable way, indicating the constant propagation of self-arrested ruptures, or unbound, for which the maximum magnitude is only limited by the size of tectonic faults and fault connectivity. Transition between the two states may occur at any time during injection or not at all. Monitoring and traffic light systems used during stimulations need to account for the possibility of unstable rupture propagation from the very beginning of injection by observing the entire seismicity evolution in near-real time and at high resolution for an immediate reaction in injection strategy. Plain Language Summary Predicting and controlling the size of earthquakes caused by fluid injection is currently the major concern of many projects associated with geothermal energy production. Here, we analyze the magnitude and seismic moment evolution with injection parameters for prominent geothermal and scientific projects to date. Evolution of seismicity seems to be largely independent of the tectonic stress background and seemingly depends on reservoir specific characteristics. We find that the maximum observed magnitudes relate linearly to the injected volume or hydraulic energy. A linear relation suggests stable growth of induced ruptures, as predicted by current models, or rupture growth may no longer depend on the stimulated volume but on tectonics. A system may change between the two states during the course of fluid injection. Close-by and high-resolution monitoring of seismic and hydraulic parameters in near-real time may help identify these fundamental changes in ample time to change injection strategy and manage maximum magnitudes.},
  language  = {en}
}
@article{ForbrigerGaoMalischewskyetal.2020,
  author    = {Forbriger, Thomas and Gao, Lingli and Malischewsky, Peter and Ohrnberger, Matthias and Pan, Yudi},
  title     = {A single Rayleigh mode may exist with multiple values of phase-velocity at one frequency},
  series = {Geophysical journal international},
  volume    = {222},
  journal   = {Geophysical journal international},
  number    = {1},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0956-540X},
  doi       = {10.1093/gji/ggaa123},
  pages     = {582 -- 594},
  year      = {2020},
  abstract  = {Other than commonly assumed in seismology, the phase velocity of Rayleigh waves is not necessarily a single-valued function of frequency. In fact, a single Rayleigh mode can exist with three different values of phase velocity at one frequency. We demonstrate this for the first higher mode on a realistic shallow seismic structure of a homogeneous layer of unconsolidated sediments on top of a half-space of solid rock (LOH). In the case of LOH a significant contrast to the half-space is required to produce the phenomenon. In a simpler structure of a homogeneous layer with fixed (rigid) bottom (LFB) the phenomenon exists for values of Poisson's ratio between 0.19 and 0.5 and is most pronounced for P-wave velocity being three times S-wave velocity (Poisson's ratio of 0.4375). A pavement-like structure (PAV) of two layers on top of a half-space produces the multivaluedness for the fundamental mode. Programs for the computation of synthetic dispersion curves are prone to trouble in such cases. Many of them use mode-follower algorithms which loose track of the dispersion curve and miss the multivalued section. We show results for well established programs. Their inability to properly handle these cases might be one reason why the phenomenon of multivaluedness went unnoticed in seismological Rayleigh wave research for so long. For the very same reason methods of dispersion analysis must fail if they imply wave number k(l)(omega) for the lth Rayleigh mode to be a single-valued function of frequency.. This applies in particular to deconvolution methods like phase-matched filters. We demonstrate that a slant-stack analysis fails in the multivalued section, while a Fourier-Bessel transformation captures the complete Rayleigh-wave signal. Waves of finite bandwidth in the multivalued section propagate with positive group-velocity and negative phase-velocity. Their eigenfunctions appear conventional and contain no conspicuous feature.},
  language  = {en}
}
@article{MengesHoviusAndermannetal.2020,
  author    = {Menges, Johanna and Hovius, Niels and Andermann, Christoff and Lupker, Maarten and Haghipour, Negar and M{\"a}rki, Lena and Sachse, Dirk},
  title     = {Variations in organic carbon sourcing along a trans-Himalayan river determined by a Bayesian mixing approach},
  series = {Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society},
  volume    = {286},
  journal   = {Geochimica et cosmochimica acta : journal of the Geochemical Society and the Meteoritical Society},
  publisher = {Elsevier},
  address   = {New York [u.a.]},
  issn      = {0016-7037},
  doi       = {10.1016/j.gca.2020.07.003},
  pages     = {159 -- 176},
  year      = {2020},
  abstract  = {Rivers transfer particulate organic carbon (POC) from eroding mountains into geological sinks. Organic carbon source composition and selective mobilization have been shown to affect the type and quantity of POC export, but their combined effects across complex mountain ranges remain underexplored. Here, we examine the variation in organic carbon sourcing and transport in the trans-Himalayan Kali Gandaki River catchment, along strong gradients in precipitation, rock type and vegetation. Combining bulk stable nitrogen, and stable and radioactive organic carbon isotopic composition of bedrock, litter, soil and river sediment samples with a Bayesian end-member mixing approach, we differentiate POC sources along the river and quantify their export. Our analysis shows that POC export from the Tibetan segment of the catchment, where carbon bearing shales are partially covered by aged and modern soils, is dominated by petrogenic POC. Based on our data we re-assess the presence of aged biospheric OC in this part of the catchment, and its contribution to the river load. In the High Himalayan segment, we observed low inputs of petrogenic and biospheric POC, likely due to very low organic carbon concentrations in the metamorphic bedrock, combined with erosion dominated by deep-seated landslides. Our findings show that along the Kali Gandaki River, the sourcing of sediment and organic carbon are decoupled, due to differences in rock organic carbon content, soil and above ground carbon stocks, and geomorphic process activity. While the fast eroding High Himalayas are the principal source of river sediment, the Tibetan headwaters, where erosion rates are lower, are the principal source of organic carbon. To robustly estimate organic carbon export from the Himalayas, the mountain range should be divided into tectono-physiographic zones with distinct organic carbon yields due to differences in substrate and erosion processes and rates.},
  language  = {en}
}
@article{ObrehtWoermerBraueretal.2020,
  author    = {Obreht, Igor and W{\"o}rmer, Lars and Brauer, Achim and Wendt, Jenny and Alfken, Susanne and De Vleeschouwer, David and Elvert, Marcus and Hinrichs, Kai-Uwe},
  title     = {An annually resolved record of Western European vegetation response to Younger Dryas cooling},
  series = {Quaternary science reviews : the international multidisciplinary research and review journal},
  volume    = {231},
  journal   = {Quaternary science reviews : the international multidisciplinary research and review journal},
  publisher = {Elsevier},
  address   = {Amsterdam [u.a.]},
  issn      = {0277-3791},
  doi       = {10.1016/j.quascirev.2020.106198},
  pages     = {15},
  year      = {2020},
  abstract  = {The regional patterns and timing of the Younger Dryas cooling in the North Atlantic realm were complex and are mechanistically incompletely understood. To enhance understanding of regional climate patterns, we present molecular biomarker records at subannual to annual resolution by mass spectrometry imaging (MSI) of sediments from the Lake Meerfelder Maar covering the Allerod-Younger Dryas transition. These analyses are supported by conventional extraction-based molecular-isotopic analyses, which both validate the imaging results and constrain the sources of the target compounds. The targeted fatty acid biomarkers serve as a gauge of the response of the local aquatic and terrestrial ecosystem to climate change. Based on the comparison of our data with existing data from Meerfelder Maar, we analyse the short-term environmental evolution in Western Europe during the studied time interval and confirm the previously reported delayed hydrological response to Greenland cooling. However, despite a detected delay of Western European environmental change of similar to 135 years, our biomarker data show statistically significant correlation with deuterium excess in Greenland ice core at - annual resolution during this time-transgressive cooling. This suggests a coherent atmospheric forcing across the North Atlantic realm during this transition. We propose that Western European cooling was postponed due to major reorganization of the westerlies that were intermittently forcing warmer and wetter air masses from lower latitudes to Western Europe and thus resulted in delayed cooling relative to Greenland.},
  language  = {en}
}
@article{KrmičekTimmermanZiemannetal.2020,
  author    = {Krm{\´i}ček, Luk{\´a}š and Timmerman, Martin Jan and Ziemann, Martin Andreas and Sudo, Masafumi and Ulrych, Jaromir},
  title     = {40Ar/39Ar step-heating dating of phlogopite and kaersutite megacrysts from the Železn{\´a} hůrka (Eisenb{\"u}hl) Pleistocene scoria cone, Czech Republic},
  series = {Geologica Carpathica},
  volume    = {71},
  journal   = {Geologica Carpathica},
  number    = {4},
  publisher = {Veda},
  address   = {Bratislava},
  issn      = {1335-0552},
  doi       = {10.31577/GeolCarp.71.4.6},
  pages     = {382 -- 387},
  year      = {2020},
  abstract  = {(40)A/Ar-39 step-heating of mica and amphibole megacrysts from hauyne-bearing olivine melilitite scoria/tephra from the Zelezna hurka yielded a 435 +/- 108 ka isotope correlation age for phlogopite and a more imprecise 1.55 Ma total gas age of the kaersutite megacryst. The amphibole megacrysts may constitute the first, and the younger phlogopite megacrysts the later phase of mafic, hydrous melilitic magma crystallization. It cannot be ruled out that the amphibole megacrysts are petrogenetically unrelated to tephra and phlogopite megacrysts and were derived from mantle xenoliths or disaggregated older, deep crustal pegmatites. This is in line both with the rarity of amphibole at Zelezna hurka and with the observed signs of magmatic resorption at the edges of amphibole crystals.},
  language  = {en}
}
@article{RybskiDawsonKropp2020,
  author    = {Rybski, Diego and Dawson, Richard J. and Kropp, J{\"u}rgen},
  title     = {Comparing generic and case study damage functions},
  series = {Natural hazards review},
  volume    = {21},
  journal   = {Natural hazards review},
  number    = {1},
  publisher = {American Society of Civil Engineers},
  address   = {Reston},
  issn      = {1527-6988},
  doi       = {10.1061/(ASCE)NH.1527-6996.0000336},
  pages     = {6},
  year      = {2020},
  abstract  = {Two different approaches are used to assess the impacts associated with natural hazards and climate change in cities. A bottom-up approach uses high resolution data on constituent assets within the urban area. In contrast, a top-down approach uses less detailed information but is consequently more readily transferable. Here, we compare damage curves generated by each approach for coastal flooding in London. To compare them, we fit a log-logistic regression with three parameters to the calculated damage curves. We find that the functions are remarkably similar in their shape, albeit with different inflection points and a maximum damage that differs by 13\%-25\%. If rescaled, the curves agree almost exactly, which enables damage assessment to be undertaken following the calculation of the three parameters.},
  language  = {en}
}
@article{BaesSobolevGeryaetal.2020,
  author    = {Baes, Marzieh and Sobolev, Stephan and Gerya, Taras V. and Brune, Sascha},
  title     = {Plume-induced subduction initiation},
  series = {Geochemistry, geophysics, geosystems},
  volume    = {21},
  journal   = {Geochemistry, geophysics, geosystems},
  number    = {2},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {1525-2027},
  doi       = {10.1029/2019GC008663},
  pages     = {19},
  year      = {2020},
  abstract  = {Initiation of subduction following the impingement of a hot buoyant mantle plume is one of the few scenarios that allow breaking the lithosphere and recycling a stagnant lid without requiring any preexisting weak zones. Here, we investigate factors controlling the number and shape of retreating subducting slabs formed by plume-lithosphere interaction. Using 3-D thermomechanical models we show that the deformation regime, which defines formation of single-slab or multi-slab subduction, depends on several parameters such as age of oceanic lithosphere, thickness of the crust and large-scale lithospheric extension rate. Our model results indicate that on present-day Earth multi-slab plume-induced subduction is initiated only if the oceanic lithosphere is relatively young (<30-40 Myr, but >10 Myr), and the crust has a typical thickness of 8 km. In turn, development of single-slab subduction is facilitated by older lithosphere and pre-imposed extensional stresses. In early Earth, plume-lithosphere interaction could have led to formation of either episodic short-lived circular subduction when the oceanic lithosphere was young or to multi-slab subduction when the lithosphere was old.},
  language  = {en}
}
@article{LiuAdlerLipusetal.2020,
  author    = {Liu, Qi and Adler, Karsten and Lipus, Daniel and K{\"a}mpf, Horst and Bussert, Robert and Plessen, Birgit and Schulz, Hans-Martin and Krauze, Patryk and Horn, Fabian and Wagner, Dirk and Mangelsdorf, Kai and Alawi, Mashal},
  title     = {Microbial signatures in deep CO2-saturated miocene sediments of the active Hartousov mofette system (NW Czech Republic)},
  series = {Frontiers in microbiology},
  volume    = {11},
  journal   = {Frontiers in microbiology},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2020.543260},
  pages     = {21},
  year      = {2020},
  abstract  = {The Hartousov mofette system is a natural CO2 degassing site in the central Cheb Basin (Eger Rift, Central Europe). In early 2016 a 108 m deep core was obtained from this system to investigate the impact of ascending mantle-derived CO2 on indigenous deep microbial communities and their surrounding life habitat. During drilling, a CO2 blow out occurred at a depth of 78.5 meter below surface (mbs) suggesting a CO2 reservoir associated with a deep low-permeable CO2-saturated saline aquifer at the transition from Early Miocene terrestrial to lacustrine sediments. Past microbial communities were investigated by hopanoids and glycerol dialkyl glycerol tetraethers (GDGTs) reflecting the environmental conditions during the time of deposition rather than showing a signal of the current deep biosphere. The composition and distribution of the deep microbial community potentially stimulated by the upward migration of CO2 starting during Mid Pleistocene time was investigated by intact polar lipids (IPLs), quantitative polymerase chain reaction (qPCR), and deoxyribonucleic acid (DNA) analysis. The deep biosphere is characterized by microorganisms that are linked to the distribution and migration of the ascending CO2-saturated groundwater and the availability of organic matter instead of being linked to single lithological units of the investigated rock profile. Our findings revealed high relative abundances of common soil and water bacteria, in particular the facultative, anaerobic and potential iron-oxidizing Acidovorax and other members of the family Comamonadaceae across the whole recovered core. The results also highlighted the frequent detection of the putative sulfate-oxidizing and CO2-fixating genus Sulfuricurvum at certain depths. A set of new IPLs are suggested to be indicative for microorganisms associated to CO2 accumulation in the mofette system.},
  language  = {en}
}
@article{MogrovejoAriasBrillWagner2020,
  author    = {Mogrovejo Arias, Diana Carolina and Brill, Florian H. H. and Wagner, Dirk},
  title     = {Potentially pathogenic bacteria isolated from diverse habitats in Spitsbergen, Svalbard},
  series = {Environmental earth sciences},
  volume    = {79},
  journal   = {Environmental earth sciences},
  number    = {5},
  publisher = {Springer},
  address   = {Berlin ; Heidelberg},
  issn      = {1866-6280},
  doi       = {10.1007/s12665-020-8853-4},
  pages     = {9},
  year      = {2020},
  abstract  = {The Arctic ecosystem, a reservoir of genetic microbial diversity, represents a virtually unlimited source of microorganisms that could interact with human beings. Despite continuous exploration of Arctic habitats and description of their microbial communities, bacterial phenotypes commonly associated with pathogenicity, such as hemolytic activity, have rarely been reported. In this study, samples of snow, fresh and marine water, soil, and sediment from several habitats in the Arctic archipelago of Svalbard were collected during Summer, 2017. Bacterial isolates were obtained after incubation on oligotrophic media at different temperatures and their hemolytic potential was assessed on sheep blood agar plates. Partial (alpha) or true (beta) hemolysis was observed in 32 out of 78 bacterial species. Genes expressing cytolytic compounds, such as hemolysins, likely increase the general fitness of the producing microorganisms and confer a competitive advantage over the availability of nutrients in natural habitats. In environmental species, the nutrient-acquisition function of these compounds presumably precedes their function as toxins for mammalian erythrocytes. However, in the light of global warming, the presence of hemolytic bacteria in Arctic environments highlights the possible risks associated with these microorganisms in the event of habitat melting/destruction, ecosystem transition, and re-colonization.},
  language  = {en}
}
@article{NiemzCescaHeimannetal.2020,
  author    = {Niemz, Peter and Cesca, Simone and Heimann, Sebastian and Grigoli, Francesco and von Specht, Sebastian and Hammer, Conny and Zang, Arno and Dahm, Torsten},
  title     = {Full-waveform-based characterization of acoustic emission activity in a mine-scale experiment},
  series = {Geophysical journal international / the Royal Astronomical Society, the Deutsche Geophysikalische Gesellschaft and the European Geophysical Society},
  volume    = {222},
  journal   = {Geophysical journal international / the Royal Astronomical Society, the Deutsche Geophysikalische Gesellschaft and the European Geophysical Society},
  number    = {1},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0955-419X},
  doi       = {10.1093/gji/ggaa127},
  pages     = {189 -- 206},
  year      = {2020},
  abstract  = {Understanding fracturing processes and the hydromechanical relation to induced seismicity is a key question for enhanced geothermal systems (EGS). Commonly massive fluid injection, predominately causing hydroshearing, are used in large-scale EGS but also hydraulic fracturing approaches were discussed. To evaluate the applicability of hydraulic fracturing techniques in EGS, six in situ, multistage hydraulic fracturing experiments with three different injection schemes were performed under controlled conditions in crystalline rock at the Aspo Hard Rock Laboratory (Sweden). During the experiments the near-field ground motion was continuously recorded by 11 piezoelectric borehole sensors with a sampling rate of 1 MHz. The sensor network covered a volume of 30x30x30 m around a horizontal, 28-m-long injection borehole at a depth of 410 m. To extract and characterize massive, induced, high-frequency acoustic emission (AE) activity from continuous recordings, a semi-automated workflow was developed relying on full waveform based detection, classification and location procedures. The approach extended the AE catalogue from 196 triggered events in previous studies to more than 19600 located AEs. The enhanced catalogue, for the first time, allows a detailed analysis of induced seismicity during single hydraulic fracturing experiments, including the individual fracturing stages and the comparison between injection schemes. Beside the detailed study of the spatio-temporal patterns, event clusters and the growth of seismic clouds, we estimate relative magnitudes and b-values of AEs for conventional, cyclic progressive and dynamic pulse injection schemes, the latter two being fatigue hydraulic fracturing techniques. While the conventional fracturing leads to AE patterns clustered in planar regions, indicating the generation of a single main fracture plane, the cyclic progressive injection scheme results in a more diffuse, cloud-like AE distribution, indicating the activation of a more complex fracture network. For a given amount of hydraulic energy (pressure multiplied by injected volume) pumped into the system, the cyclic progressive scheme is characterized by a lower rate of seismicity, lower maximum magnitudes and significantly larger b-values, implying an increased number of small events relative to the large ones. To our knowledge, this is the first direct comparison of high resolution seismicity in a mine-scale experiment induced by different hydraulic fracturing schemes.},
  language  = {en}
}
@article{WangDresenRybackietal.2020,
  author    = {Wang, Lei and Dresen, Georg and Rybacki, Erik and Bonnelye, Audrey and Bohnhoff, Marco},
  title     = {Pressure-dependent bulk compressibility of a porous granular material modeled by improved contact mechanics and micromechanical approaches},
  series = {Acta materialia},
  volume    = {188},
  journal   = {Acta materialia},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1359-6454},
  doi       = {10.1016/j.actamat.2020.01.063},
  pages     = {259 -- 272},
  year      = {2020},
  abstract  = {The change of the mechanical properties of granular materials with pressure is an important topic associated with many industrial applications. In this paper we investigate the influence of hydrostatic pressure (P-e) on the effective bulk compressibility (C-eff) of a granular material by applying two modified theoretical approaches that are based on contact mechanics and micromechanics, respectively. For a granular material composed of rough grains, an extended contact model is developed to elucidate the effect of roughness of grain surfaces on bulk compressibility. At relatively low pressures, the model predicts that the decrease of bulk compressibility with pressure may be described by a power law with an exponent of -1/2 (i.e., C-eff proportional to P-e(1/2) ), but deviates at intermediate pressures. At elevated pressures beyond full contact, bulk compressibility remains almost unchanged, which may be roughly evaluated by continuum contact mechanics. As an alternative explanation of pressure-dependent bulk compressibility, we suggest a micromechanical model that accounts for effects of different types of pore space present in granular materials. Narrow and compliant inter-granular cracks are approximated by three-dimensional oblate spheroidal cracks with rough surfaces, whereas the equant and stiff pores surrounded by three and four neighboring grains are modeled as tubular pores with cross sections of three and four cusp-like corners, respectively. In this model, bulk compressibility is strongly reduced with increasing pressure by progressive closure of rough-walled cracks. At pressures exceeding crack closure pressure, deformation of the remaining equant pores is largely insensitive to pressure, with almost no further change in bulk compressibility. To validate these models, we performed hydrostatic compression tests on Bentheim sandstone (a granular rock consisting of quartz with high porosity) under a wide range of pressure. The relation between observed microstructures and measured pressure-dependent bulk compressibility is well explained by both suggested models.},
  language  = {en}
}
@article{PradhanKriewaldCostaetal.2020,
  author    = {Pradhan, Prajal and Kriewald, Steffen and Costa, Lu{\´i}s F{\´i}l{\´i}pe Carvalho da and Rybski, Diego and Benton, Tim G. and Fischer, G{\"u}nther and Kropp, J{\"u}rgen},
  title     = {Urban food systems: how regionalization can contribute to climate change mitigation},
  series = {Environmental science \& technology},
  volume    = {54},
  journal   = {Environmental science \& technology},
  number    = {17},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0013-936X},
  doi       = {10.1021/acs.est.0c02739},
  pages     = {10551 -- 10560},
  year      = {2020},
  abstract  = {Cities will play a key role in the grand challenge of nourishing a growing global population, because, due to their population density, they set the demand. To ensure that food systems are sustainable, as well as nourishing, one solution often suggested is to shorten their supply chains toward a regional rather than a global basis. While such regional systems may have a range of costs and benefits, we investigate the mitigation potential of regionalized urban food systems by examining the greenhouse gas emissions associated with food transport. Using data on food consumption for 7108 urban administrative units (UAUs), we simulate total transport emissions for both regionalized and globalized supply chains. In regionalized systems, the UAUs' demands are fulfilled by peripheral food production, whereas to simulate global supply chains, food demand is met from an international pool (where the origin can be any location globally). We estimate that regionalized systems could reduce current emissions from food transport. However, because longer supply chains benefit from maximizing comparative advantage, this emission reduction would require closing yield gaps, reducing food waste, shifting toward diversified farming, and consuming seasonal produce. Regionalization of food systems will be an essential component to limit global warming to well below 2 degrees C in the future.},
  language  = {en}
}
@article{SchoenfeldtPanekWinocuretal.2020,
  author    = {Sch{\"o}nfeldt, Elisabeth and P{\´a}nek, Tom{\´a}š and Winocur, Diego and Silhan, Karel and Korup, Oliver},
  title     = {Postglacial Patagonian mass movement},
  series = {Geomorphology : an international journal on pure and applied geomorphology},
  volume    = {367},
  journal   = {Geomorphology : an international journal on pure and applied geomorphology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0169-555X},
  doi       = {10.1016/j.geomorph.2020.107316},
  pages     = {16},
  year      = {2020},
  abstract  = {Many of the volcanic plateau margins of the eastern, formerly glaciated, foreland of the Patagonian Andes are undermined by giant landslides (>= 10(8) m(3)). One cluster of such landslides extends along the margin of the Meseta del Lago Buenos Aires (MLBA) plateau that is formed mainly by Neogene-Quaternary basalts. The dry climate is at odds with numerous >2-km long earthflows nested within older and larger compound landslides. We present a hydrological analysis, a detailed geomorphic map, interpretations of exposed landslide interiors, and radiocarbon dating of the El Mirador landslide, which is one of the largest and morphologically most representative landslide. We find that the presence of lakes on top of the plateau, causing low infiltration rates, correlates negatively with the abundance of earthflows on compound landslides along the plateau margins. Field outcrops show that the pattern of compound landslides and earthflows is likely controlled by groundwater seepage at the contact between the basalts and underlying soft Miocene molasse. Numerous peat bogs store water and sediment and are more abundant in earthflow-affected areas than in their contributing catchment areas. <br /> Radiocarbon dates indicate that these earthflows displaced metre-thick layers of peat in the late Holocene (<2.5 ka). We conclude that earthflows of the MLBA plateau might be promising proxies of past hydroclimatic conditions in the Patagonian foreland, if strong earthquakes or gradual crustal stress changes due to glacioisostatic rebound can be ruled out.},
  language  = {en}
}
@article{ScherlerSchwanghart2020,
  author    = {Scherler, Dirk and Schwanghart, Wolfgang},
  title     = {Drainage divide networks},
  series = {Earth surface dynamics},
  volume    = {8},
  journal   = {Earth surface dynamics},
  number    = {2},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {2196-6311},
  doi       = {10.5194/esurf-8-261-2020},
  pages     = {261 -- 274},
  year      = {2020},
  abstract  = {Drainage divides are organized into tree-like networks that may record information about drainage divide mobility. However, views diverge about how to best assess divide mobility. Here, we apply a new approach of automatically extracting and ordering drainage divide networks from digital elevation models to results from landscape evolution model experiments. We compared landscapes perturbed by strike-slip faulting and spatiotemporal variations in erodibility to a reference model to assess which topographic metrics (hillslope relief, flow distance, and chi) are diagnostic of divide mobility. Results show that divide segments that are a minimum distance of similar to 5 km from river confluences strive to attain constant values of hillslope relief and flow distance to the nearest stream. Disruptions of such patterns can be related to mobile divides that are lower than stable divides, closer to streams, and often asymmetric in shape. In general, we observe that drainage divides high up in the network, i.e., at great distances from river confluences, are more susceptible to disruptions than divides closer to these confluences and are thus more likely to record disturbance for a longer time period. We found that across-divide differences in hillslope relief proved more useful for assessing divide migration than other tested metrics. However, even stable drainage divide networks exhibit across-divide differences in any of the studied topographic metrics. Finally, we propose a new metric to quantify the connectivity of divide junctions.},
  language  = {en}
}
@article{EsfahaniGholamiOhrnberger2020,
  author    = {Esfahani, Reza Dokht Dolatabadi and Gholami, Ali and Ohrnberger, Matthias},
  title     = {An inexact augmented Lagrangian method for nonlinear dispersion-curve inversion using Dix-type global linear approximation},
  series = {Geophysics},
  volume    = {85},
  journal   = {Geophysics},
  number    = {5},
  publisher = {Society of Exploration Geophysicists},
  address   = {Tulsa},
  issn      = {0016-8033},
  doi       = {10.1190/GEO2019-0717.1},
  pages     = {EN77 -- EN85},
  year      = {2020},
  abstract  = {Dispersion-curve inversion of Rayleigh waves to infer subsurface shear-wave velocity is a long-standing problem in seismology. Due to nonlinearity and ill-posedness, sophisticated regularization techniques are required to solve the problem for a stable velocity model. We have formulated the problem as a minimization problem with nonlinear operator constraint and then solve it by using an inexact augmented Lagrangian method, taking advantage of the Haney-Tsai Dix-type relation (a global linear approximation of the nonlinear forward operator). This replaces the original regularized nonlinear problem with iterative minimization of a more tractable regularized linear problem followed by a nonlinear update of the phase velocity (data) in which the update can be performed accurately with any forward modeling engine, for example, the finite-element method. The algorithm allows discretizing the medium with thin layers (for the finite-element method) and thus omitting the layer thicknesses from the unknowns and also allows incorporating arbitrary regularizations to shape the desired velocity model. In this research, we use total variation regularization to retrieve the shear-wave velocity model. We use two synthetic and two real data examples to illustrate the performance of the inversion algorithm with total variation regularization. We find that the method is fast and stable, and it converges to the solution of the original nonlinear problem.},
  language  = {en}
}
@article{SieberBrinkLeysetal.2020,
  author    = {Sieber, Melanie Jutta and Brink, Frank J. and Leys, Clyde and King, Penelope L. and Henley, Richard W.},
  title     = {Prograde and retrograde metasomatic reactions in mineralised magnesium- silicate skarn in the Cu-Au Ertsberg East Skarn System, Ertsberg, Papua Province, Indonesia},
  series = {Ore geology reviews},
  volume    = {125},
  journal   = {Ore geology reviews},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0169-1368},
  doi       = {10.1016/j.oregeorev.2020.103697},
  pages     = {14},
  year      = {2020},
  abstract  = {The 2.7-2.9 Ma Ertsberg East Skarn System (EESS) is a world-class Cu-Au skarn that formed within and adjacent to an intrusion within a paleodepth of 0.5 km and > 2.5 km. Its economic mineralisation developed by sustained reaction of magmatic fluid with contact metamorphosed siliciclastic and carbonate rocks at the margin of the adjacent Ertsberg quartz monzodiorite intrusion. Based on high-resolution mineral mapping, chemical analysis and thermodynamic calculations, the multistage formation processes of the exoskarn components of the EESS are examined in the context of changing pressure, temperature, fluid composition and fluid phase. We show that contact metamorphism of dolomitic sediments occurred at 51 +/- 5 MPa, between 700 degrees C and 800 degrees C and in the presence of a H2O-CO2-fluid containing similar to 10 to similar to 70 mol\% CO2. This prograde metamorphism formed a forsterite + diopside + calcite + phlogopite + spinel assemblage. Such forsterite-dominated skarns account for similar to 55 vol\% of the EESS exoskarns. Rare pargasite (previously unrecognized in this deposit) formed locally in the metamorphosed carbonate sequence where the protolith was composed of supratidal evaporites with dolomitic carbonate and interlayered calc-silicate rocks. The subsequent flux of a lower pressure magmatic gas containing SO2(g) caused sulphate metasomatism. This high temperature gas alteration of the metamorphic assemblage also caused skarn Cu-Fe-sulphide mineralisation. The influx of a SO2 gas through fracture permeability occurred at a temperature between similar to 600 and 700 degrees C and caused calcite to be replaced by anhydrite, with the coupled release of H2S(g). This in-situ release of H2S(g) scavenged trace Cu from the gas phase to deposit Cu-Fe-sulphides, which make the economic value of the distinct. We demonstrate that the formation of metal sulphides within forsterite skarns of the Ertsberg East Skarn System required a minimum flux of similar to 1,050 Mt SO2(g) and show that volcanic degassing may have occurred over a time span of similar to 3,900 years. As the system waned, the ambient fluid resulted in partial retrograde serpentinization of olivine and diopside without carbonation, and at temperatures sufficiently high to preserve anhydrite.},
  language  = {en}
}
@article{ZhangYangJomaaetal.2020,
  author    = {Zhang, Xiaolin and Yang, Xiaoqiang and Jomaa, Seifeddine and Rode, Michael},
  title     = {Analyzing impacts of seasonality and landscape gradient on event-scale nitrate-discharge dynamics based on nested high-frequency monitoring},
  series = {Journal of hydrology},
  volume    = {591},
  journal   = {Journal of hydrology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0022-1694},
  doi       = {10.1016/j.jhydrol.2020.125585},
  pages     = {12},
  year      = {2020},
  abstract  = {Increasingly available high-frequency data during storm events, when hydrological dynamics most likely activate nitrate storage-flux exchanges, reveal insights into catchment nitrate dynamics. In this study, we explored impacts of seasonality and landscape gradients on nitrate concentration-discharge (C-Q) hysteresis patterns in the Selke catchment, central Germany, which has heterogeneous combinations of meteorological, hydrogeological and land use conditions. Three nested gauging stations established along the main Selke River captured flow and nitrate export dynamics from the uppermost subcatchment (mixed forest and arable land), middle subcatchment (pure steep forest) and lowermost subcatchment (arable and urban land). We collected continuous high-frequency (15-min) discharge and nitrate concentration data from 2012 to 2017 and analyzed the 223 events detected at all three stations. A dominant hysteresis pattern in the uppermost and middle subcatchments was counter-clockwise and combined with an accretion effect, indicating many proximal and mobilized distal nitrate sources. However, 66\% of all events at the catchment outlet experienced a dilution effect, possibly due to mechanisms that vary seasonally. During wetting/wet periods (October-March), it was combined mainly with a counter-clockwise pattern due to the dominance of event runoff volume from the uppermost and middle subcatchments. During drying/dry periods (April-September), however, it was combined mainly with a clockwise pattern due to occasional quick surface flows from lowland near-stream urban areas. In addition, the clockwise hysteresis occurred mainly from May-October during mostly drying/dry periods at all three sites, indicating little distal nitrate transport in response to the low terrestrial hydrological connectivity, especially in the lowermost dry and flat sub-catchment. This comprehensive analysis (i.e., clockwise vs. counter-clockwise, accretion vs. dilution) enables in-depth analysis of nitrate export mechanisms during certain periods under different landscape conditions. Specific combination of C-Q relationships could identify target locations for agricultural management actions that decrease nitrate output. Therefore, we strongly encourage long-term multisite and high-frequency monitoring strategies in heterogeneous nested catchment(s), which can help understand process mechanisms, generate data for physical-based water-quality modeling and provide guidance for water and agricultural management.},
  language  = {en}
}
@article{AlbrechtWinkelmannLevermann2020,
  author    = {Albrecht, Torsten and Winkelmann, Ricarda and Levermann, Anders},
  title     = {Glacial-cycle simulations of the Antarctic Ice Sheet with the Parallel Ice Sheet Model (PISM)},
  series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
  volume    = {14},
  journal   = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
  number    = {2},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1994-0416},
  doi       = {10.5194/tc-14-599-2020},
  pages     = {599 -- 632},
  year      = {2020},
  abstract  = {Simulations of the glacial-interglacial history of the Antarctic Ice Sheet provide insights into dynamic threshold behavior and estimates of the ice sheet's contributions to global sea-level changes for the past, present and future. However, boundary conditions are weakly constrained, in particular at the interface of the ice sheet and the bedrock. Also climatic forcing covering the last glacial cycles is uncertain, as it is based on sparse proxy data. <br /> We use the Parallel Ice Sheet Model (PISM) to investigate the dynamic effects of different choices of input data, e.g., for modern basal heat flux or reconstructions of past changes of sea level and surface temperature. As computational resources are limited, glacial-cycle simulations are performed using a comparably coarse model grid of 16 km and various parameterizations, e.g., for basal sliding, iceberg calving, or for past variations in precipitation and ocean temperatures. In this study we evaluate the model's transient sensitivity to corresponding parameter choices and to different boundary conditions over the last two glacial cycles and provide estimates of involved uncertainties. We also discuss isolated and combined effects of climate and sea-level forcing. Hence, this study serves as a "cookbook" for the growing community of PISM users and paleo-ice sheet modelers in general. <br /> For each of the different model uncertainties with regard to climatic forcing, ice and Earth dynamics, and basal processes, we select one representative model parameter that captures relevant uncertainties and motivates corresponding parameter ranges that bound the observed ice volume at present. The four selected parameters are systematically varied in a parameter ensemble analysis, which is described in a companion paper.},
  language  = {en}
}
@article{FigueroaVillegasWeissHongnetal.2020,
  author    = {Figueroa Villegas, Sara and Weiss, Jonathan R. and Hongn, Fernando D. and Pingel, Heiko and Escalante, Leonardo and El{\´i}as, Leonardo and Aranda-Viana, R. Germ{\´a}n and Strecker, Manfred},
  title     = {Late pleistocene to recent deformation in the thick-skinned fold-and-thrust belt of Northwestern Argentina (Central Calchaqui Valley, 26 degrees S)},
  series = {Tectonics / American Geophysical Union, AGU ; European Geophysical Society, EGS},
  volume    = {40},
  journal   = {Tectonics / American Geophysical Union, AGU ; European Geophysical Society, EGS},
  number    = {1},
  publisher = {American Geophysical Union},
  address   = {Washington, DC},
  issn      = {0278-7407},
  doi       = {10.1029/2020TC006394},
  pages     = {20},
  year      = {2020},
  abstract  = {The thick-skinned fold-and-thrust belt on the eastern flank of the Andean Plateau in northwestern Argentina (NWA) is a zone of active contractional deformation characterized by fault-bounded mountain ranges with no systematic spatiotemporal pattern of tectonic activity. In contrast, the thin-skinned Subandean fold-and-thrust belt of northern Argentina and southern Bolivia is characterized primarily by in-sequence (i.e., west to east) fault progression, with a narrow zone of Quaternary deformation focused at the front of the orogenic wedge. To better understand how recent deformation is accommodated across these mountain ranges and the Argentinian portion of the orogen in particular, estimating and comparing deformation rates and patterns across different timescales is essential. We present Late Pleistocene shortening rates for the central Calchaqui intermontane valley in NWA associated with at least three episodes of deformation. Global Positioning System data for the same region reveal a gradual decrease in horizontal surface velocities from the Eastern Cordillera toward the foreland, which contrasts with the rapid velocity gradient associated with a locked decollement in the Subandean Ranges of southern Bolivia. Our new results represent a small view of regional deformation that, when considered in combination with the shallow crustal seismicity and decadal-scale surface velocities, support the notion that strain release in NWA is associated with numerous slowly deforming structures that are distributed throughout the orogen.},
  language  = {en}
}
@article{WetzelKempkaKuehn2020,
  author    = {Wetzel, Maria and Kempka, Thomas and K{\"u}hn, Michael},
  title     = {Hydraulic and mechanical impacts of pore space alterations within a sandstone quantified by a flow velocity-dependent precipitation approach},
  series = {Materials},
  volume    = {13},
  journal   = {Materials},
  number    = {14},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1996-1944},
  doi       = {10.3390/ma13143100},
  pages     = {20},
  year      = {2020},
  abstract  = {Geochemical processes change the microstructure of rocks and thereby affect their physical behaviour at the macro scale. A micro-computer tomography (micro-CT) scan of a typical reservoir sandstone is used to numerically examine the impact of three spatial alteration patterns on pore morphology, permeability and elastic moduli by correlating precipitation with the local flow velocity magnitude. The results demonstrate that the location of mineral growth strongly affects the permeability decrease with variations by up to four orders in magnitude. Precipitation in regions of high flow velocities is characterised by a predominant clogging of pore throats and a drastic permeability reduction, which can be roughly described by the power law relation with an exponent of 20. A continuous alteration of the pore structure by uniform mineral growth reduces the permeability comparable to the power law with an exponent of four or the Kozeny-Carman relation. Preferential precipitation in regions of low flow velocities predominantly affects smaller throats and pores with a minor impact on the flow regime, where the permeability decrease is considerably below that calculated by the power law with an exponent of two. Despite their complete distinctive impact on hydraulics, the spatial precipitation patterns only slightly affect the increase in elastic rock properties with differences by up to 6.3\% between the investigated scenarios. Hence, an adequate characterisation of the spatial precipitation pattern is crucial to quantify changes in hydraulic rock properties, whereas the present study shows that its impact on elastic rock parameters is limited. The calculated relations between porosity and permeability, as well as elastic moduli can be applied for upscaling micro-scale findings to reservoir-scale models to improve their predictive capabilities, what is of paramount importance for a sustainable utilisation of the geological subsurface.},
  language  = {en}
}
@article{ChengMilsch2020,
  author    = {Cheng, Chaojie and Milsch, Harald},
  title     = {Evolution of fracture aperture in quartz sandstone under hydrothermal conditions},
  series = {Minerals},
  volume    = {10},
  journal   = {Minerals},
  number    = {8},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2075-163X},
  doi       = {10.3390/min10080657},
  pages     = {18},
  year      = {2020},
  abstract  = {Fractures efficiently affect fluid flow in geological formations, and thereby determine mass and energy transport in reservoirs, which are not least exploited for economic resources. In this context, their response to mechanical and thermal changes, as well as fluid-rock interactions, is of paramount importance. In this study, a two-stage flow-through experiment was conducted on a pure quartz sandstone core of low matrix permeability, containing one single macroscopic tensile fracture. In the first short-term stage, the effects of mechanical and hydraulic aperture on pressure and temperature cycles were investigated. The purpose of the subsequent intermittent-flow long-term (140 days) stage was to constrain the evolution of the geometrical and hydraulic fracture properties resulting from pressure solution. Deionized water was used as the pore fluid, and permeability, as well as the effluent Si concentrations, were systematically measured. Overall, hydraulic aperture was shown to be significantly less affected by pressure, temperature and time, in comparison to mechanical aperture. During the long-term part of the experiment at 140 degrees C, the effluent Si concentrations likely reached a chemical equilibrium state within less than 8 days of stagnant flow, and exceeded the corresponding hydrostatic quartz solubility at this temperature. This implies that the pressure solution was active at the contacting fracture asperities, both at 140 degrees C and after cooling to 33 degrees C. The higher temperature yielded a higher dissolution rate and, consequently, a faster attainment of chemical equilibrium within the contact fluid. X-ray mu CT observations evidenced a noticeable increase in fracture contact area ratio, which, in combination with theoretical considerations, implies a significant decrease in mechanical aperture. In contrast, the sample permeability, and thus the hydraulic fracture aperture, virtually did not vary. In conclusion, pressure solution-induced fracture aperture changes are affected by the degree of time-dependent variations in pore fluid composition. In contrast to the present case of a quasi-closed system with mostly stagnant flow, in an open system with continuous once-through fluid flow, the activity of the pressure solution may be amplified due to the persistent fluid-chemical nonequilibrium state, thus possibly enhancing aperture and fracture permeability changes.},
  language  = {en}
}
@article{CookTurowskiHovius2020,
  author    = {Cook, Kristen L. and Turowski, Jens M. and Hovius, Niels},
  title     = {Width control on event-scale deposition and evacuation of sediment in bedrock-confined channels},
  series = {Earth surface processes and landforms : the journal of the British Geomorphological Research Group},
  volume    = {45},
  journal   = {Earth surface processes and landforms : the journal of the British Geomorphological Research Group},
  number    = {14},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0197-9337},
  doi       = {10.1002/esp.4993},
  pages     = {3702 -- 3713},
  year      = {2020},
  abstract  = {In mixed bedrock-alluvial rivers, the response of the system to a flood event can be affected by a number of factors, including coarse sediment availability in the channel, sediment supply from the hillslopes and upstream, flood sequencing and coarse sediment grain size distribution. However, the impact of along-stream changes in channel width on bedload transport dynamics remains largely unexplored. We combine field data, theory and numerical modelling to address this gap. First, we present observations from the Daan River gorge in western Taiwan, where the river flows through a 1 km long 20-50 m wide bedrock gorge bounded upstream and downstream by wide braidplains. We documented two flood events during which coarse sediment evacuation and redeposition appear to cause changes of up to several metres in channel bed elevation. Motivated by this case study, we examined the relationships between discharge, channel width and bedload transport capacity, and show that for a given slope narrow channels transport bedload more efficiently than wide ones at low discharges, whereas wider channels are more efficient at high discharges. We used the model sedFlow to explore this effect, running a random sequence of floods through a channel with a narrow gorge section bounded upstream and downstream by wider reaches. Channel response to imposed floods is complex, as high and low discharges drive different spatial patterns of erosion and deposition, and the channel may experience both of these regimes during the peak and recession periods of each flood. Our modelling suggests that width differences alone can drive substantial variations in sediment flux and bed response, without the need for variations in sediment supply or mobility. The fluctuations in sediment transport rates that result from width variations can lead to intermittent bed exposure, driving incision in different segments of the channel during different portions of the hydrograph.},
  language  = {en}
}
@article{WieczorekHerzschuh2020,
  author    = {Wieczorek, Mareike and Herzschuh, Ulrike},
  title     = {Compilation of relative pollen productivity (RPP) estimates and taxonomically harmonised RPP datasets for single continents and Northern Hemisphere extratropics},
  series = {Earth system science data : ESSD},
  volume    = {12},
  journal   = {Earth system science data : ESSD},
  number    = {4},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1866-3508},
  doi       = {10.5194/essd-12-3515-2020},
  pages     = {3515 -- 3528},
  year      = {2020},
  abstract  = {Relative pollen productivity (RPP) estimates are fractionate values, often in relation to Poaceae, that allow vegetation cover to be estimated from pollen counts with the help of models. RPP estimates are especially used in the scientific community in Europe and China, with a few studies in North America. Here we present a comprehensive compilation of available northern hemispheric RPP studies and their results arising from 51 publications with 60 sites and 131 taxa. This compilation allows scientists to identify data gaps in need of further RPP analyses but can also aid them in finding an RPP set for their study region. We also present a taxonomically harmonised, unified RPP dataset for the Northern Hemisphere and subsets for North America (including Greenland), Europe (including arctic Russia), and China, which we generated from the available studies. The unified dataset gives the mean RPP for 55 harmonised taxa as well as fall speeds, which are necessary to reconstruct vegetation cover from pollen counts and RPP values. Data are openly available at https://doi.org/10.1594/PANGAEA.922661 (Wieczorek and Herzschuh, 2020).},
  language  = {en}
}
@article{HeeschenJanochaSpangenbergetal.2020,
  author    = {Heeschen, Katja U. and Janocha, Julian and Spangenberg, Erik and Schicks, Judith Maria and Giese, Ronny},
  title     = {The impact of ice on the tensile strength of unconsolidated sand},
  series = {Marine and petroleum geology},
  volume    = {122},
  journal   = {Marine and petroleum geology},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0264-8172},
  doi       = {10.1016/j.marpetgeo.2020.104607},
  pages     = {9},
  year      = {2020},
  abstract  = {Tensile strength is an important parameter when it comes to predictions of potential fracturing of sediments by natural processes such as the emplacement of ice or gas hydrate lenses, as well as anthropogenic fracturing or else the stability of engineering constructions such as boreholes. Yet, tensile strength (sigma(tau)) measurements of unconsolidated ice-bearing or gas hydrate-bearing sands are scarce and affected by a large variability. <br /> In the course of the SUGAR project we successfully used ice as a model for pore-filling and "load-bearing" gas hydrate in sand to determine compressional wave velocity. We were thus able to verify comparable formation characteristics and morphologies of ice and gas hydrate within the pore space. As these are important values for the tensile strength of ice/hydrate-bearing sands, ice was also used as a model for hydrate-bearing sands, despite differences in the mechanical behavior and strength of pure ice and gas hydrate. Water-saturated sand cores with ice saturations (S-ice) between 0 and 100\% were tested at -6.8 degrees C. The varying S-ice were a result of the freezing point depression caused by saline solutions of different concentrations. The sigma(tau) was directly determined using a sleeve-fracturing test with an internal pressure that was created within the frozen samples. The setup was also adapted to fit a pressure vessel for tests using confining pressure. <br /> The correlation of S-ice - sigma(tau) shows an exponential increase of sigma(tau) with S-ice. Whereas at S-ice < 60\% the increase is small, it is large at S-ice > 80\%. In conjunction with the change in strength, the viscoelastic behavior changes. A clear peak strength occurs at S-ice > 80\%. We conclude that given 60\% < S-ice < 80\% the pore-filling morphology of the ice converts into a frame-building habitus and at S-ice > 80\% the frame gains strength while the amount of residual water decreases. Tensile failure and cracking now exceed grain boundary sliding as the prevailing failure mode. The ice morphology in the sand is non-cementing and comparable to a gas hydrate-sand mixture.},
  language  = {en}
}
@article{WeatherillKothaCotton2020,
  author    = {Weatherill, Graeme and Kotha, Sreeram Reddy and Cotton, Fabrice Pierre},
  title     = {Re-thinking site amplification in regional seismic risk assessment},
  series = {Earthquake spectra : the professional journal of the Earthquake Engineering Research Institute},
  volume    = {36},
  journal   = {Earthquake spectra : the professional journal of the Earthquake Engineering Research Institute},
  number    = {1_SUPPL},
  publisher = {Sage Publishing},
  address   = {Thousand Oaks, CA},
  issn      = {8755-2930},
  doi       = {10.1177/8755293019899956},
  pages     = {274 -- 297},
  year      = {2020},
  abstract  = {Probabilistic assessment of seismic hazard and risk over a geographical region presents the modeler with challenges in the characterization of the site amplification that are not present in site-specific assessment. Using site-to-site residuals from a ground motion model fit to observations from the Japanese KiK-net database, correlations between measured local amplifications and mappable proxies such as topographic slope and geology are explored. These are used subsequently to develop empirical models describing amplification as a direct function of slope, conditional upon geological period. These correlations also demonstrate the limitations of inferring 30-m shearwave velocity from slope and applying them directly into ground motion models. Instead, they illustrate the feasibility of deriving spectral acceleration amplification factors directly from sets of observed records, which are calibrated to parameters that can be mapped uniformly on a regional scale. The result is a geologically calibrated amplification model that can be incorporated into national and regional seismic hazard and risk assessment, ensuring that the corresponding total aleatory variability reflects the predictive capability of the mapped site proxy.},
  language  = {en}
}
@article{PutraPradhanKropp2020,
  author    = {Putra, Muhammad Panji Islam Fajar and Pradhan, Prajal and Kropp, J{\"u}rgen},
  title     = {A systematic analysis of Water-Energy-Food security nexus},
  series = {The science of the total environment : an international journal for scientific research into the environment and its relationship with man},
  volume    = {728},
  journal   = {The science of the total environment : an international journal for scientific research into the environment and its relationship with man},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0048-9697},
  doi       = {10.1016/j.scitotenv.2020.138451},
  pages     = {9},
  year      = {2020},
  abstract  = {Most South Asian countries have challenges in ensuring water, energy, and food (WEF) security, which are often interacting positively or negatively. To address these challenges, the nexus approach provides a framework to identify the interactions of the WEF sectors as an integrated system. However, most nexus studies only qualitatively discuss the interactions between these sectors. This study conducts a systematic analysis of the WEF security nexus in South Asia by using open data sources at the country scale. We analyze interactions between the WEF sectors statistically, defining positive and negative correlations between the WEF security indicators as synergies and trade-offs, respectively. By creating networks of the synergies and trade-offs, we further identify most positively and negatively influencing indicators in the WEF security nexus. We observe a larger share of trade-offs than synergies within the water and energy sectors and a larger share of synergies than trade-offs among the WEF sectors for South Asia. However, these observations vary across the South Asian countries. Our analysis highlights that strategies on promoting sustainable energy and discouraging fossil fuel use could have overall positive effects on the WEF security nexus in the countries. This study provides evidence for considering the WEF security nexus as an integrated system rather than just a combination of three different sectors or securities.},
  language  = {en}
}
@article{Specht2020,
  author    = {Specht, Sebastian von},
  title     = {ICBM Integrated Combined Baseline Modification},
  series = {Seismological research letters},
  volume    = {91},
  journal   = {Seismological research letters},
  number    = {1},
  publisher = {Seismological Society of America, Eastern Section},
  address   = {Boulder, Colo.},
  issn      = {0895-0695},
  doi       = {10.1785/0220190134},
  pages     = {475 -- 487},
  year      = {2020},
  abstract  = {Accelerograms are the primary source for characterizing strong ground motion. It is therefore of paramount interest to have high-quality recordings free from any nonphysical contamination. Frequently, accelerograms are affected by baseline jumps and drifts, either related to the instrument and/or a major earthquake. In this work, I propose a correction method for these undesired baseline drifts based on segmented linear least squares. The algorithm operates on the integrated waveforms and combines all three instrument components to estimate a model that modifies the baseline to be at zero continuously. The procedure consists of two steps: first a suite of models with variable numbers of discontinuities is derived for all three instrument components. During this process, the number of discontinuities is reduced in a parsimonious way, for example, two very close discontinuities are merged into a single one. In the second step, the optimal model is selected on the basis of the Bayesian information criterion. I exemplify the application on synthetic waveforms with known discontinuities and on observed waveforms from a unified strong-motion database of the Japan Meteorological Agency (JMA) and the National Research Institute for Earth Science and Disaster Prevention (NIED, Japan) networks for the major events of the 2016 Kumamoto earthquakes. After the baseline jump correction, the waveforms are furthermore corrected for displacement according to Wang et al.(2011). The resulting displacements are comparable to the Interferometric Synthetic Aperture Radar-derived displacement estimates for the Kumamoto earthquake sequence.},
  language  = {en}
}
@article{KaramzadehToularoudHeimannDahmetal.2020,
  author    = {Karamzadeh Toularoud, Nasim and Heimann, Sebastian and Dahm, Torsten and Kr{\"u}ger, Frank},
  title     = {Earthquake source arrays},
  series = {Geophysical journal international},
  volume    = {221},
  journal   = {Geophysical journal international},
  number    = {1},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0956-540X},
  doi       = {10.1093/gji/ggaa002},
  pages     = {352 -- 370},
  year      = {2020},
  abstract  = {A collection of earthquake sources recorded at a single station, under specific conditions, are considered as a source array (SA), that is interpreted as if earthquake sources originate at the station location and are recorded at the source location. Then, array processing methods, that is array beamforming, are applicable to analyse the recorded signals. A possible application is to use source array multiple event techniques to locate and characterize near-source scatterers and structural interfaces. In this work the aim is to facilitate the use of earthquake source arrays by presenting an automatic search algorithm to configure the source array elements. We developed a procedure to search for an optimal source array element distribution given an earthquake catalogue including accurate origin time and hypocentre locations. The objective function of the optimization process can be flexibly defined for each application to ensure the prerequisites (criteria) of making a source array. We formulated four quantitative criteria as subfunctions and used the weighted sum technique to combine them in one single scalar function. The criteria are: (1) to control the accuracy of the slowness vector estimation using the time domain beamforming method, (2) to measure the waveform coherency of the array elements, (3) to select events with lower location error and (4) to select traces with high energy of specific phases, that is, sp- or ps-phases. The proposed procedure is verified using synthetic data as well as real examples for the Vogtland region in Northwest Bohemia. We discussed the possible application of the optimized source arrays to identify the location of scatterers in the velocity model by presenting a synthetic test and an example using real waveforms.},
  language  = {en}
}
@article{MorishitaLazeckyWrightetal.2020,
  author    = {Morishita, Yu and Lazecky, Milan and Wright, Tim J. and Weiss, Jonathan R. and Elliott, John R. and Hooper, Andy},
  title     = {LiCSBAS},
  series = {Remote sensing},
  volume    = {12},
  journal   = {Remote sensing},
  number    = {3},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2072-4292},
  doi       = {10.3390/rs12030424},
  pages     = {29},
  year      = {2020},
  abstract  = {For the past five years, the 2-satellite Sentinel-1 constellation has provided abundant and useful Synthetic Aperture Radar (SAR) data, which have the potential to reveal global ground surface deformation at high spatial and temporal resolutions. However, for most users, fully exploiting the large amount of associated data is challenging, especially over wide areas. To help address this challenge, we have developed LiCSBAS, an open-source SAR interferometry (InSAR) time series analysis package that integrates with the automated Sentinel-1 InSAR processor (LiCSAR). LiCSBAS utilizes freely available LiCSAR products, and users can save processing time and disk space while obtaining the results of InSAR time series analysis. In the LiCSBAS processing scheme, interferograms with many unwrapping errors are automatically identified by loop closure and removed. Reliable time series and velocities are derived with the aid of masking using several noise indices. The easy implementation of atmospheric corrections to reduce noise is achieved with the Generic Atmospheric Correction Online Service for InSAR (GACOS). Using case studies in southern Tohoku and the Echigo Plain, Japan, we demonstrate that LiCSBAS applied to LiCSAR products can detect both large-scale (>100 km) and localized (similar to km) relative displacements with an accuracy of <1 cm/epoch and similar to 2 mm/yr. We detect displacements with different temporal characteristics, including linear, periodic, and episodic, in Niigata, Ojiya, and Sanjo City, respectively. LiCSBAS and LiCSAR products facilitate greater exploitation of globally available and abundant SAR datasets and enhance their applications for scientific research and societal benefit.},
  language  = {en}
}
@article{ZhuCottonPilz2020,
  author    = {Zhu, Chuanbin and Cotton, Fabrice Pierre and Pilz, Marco},
  title     = {Detecting site resonant frequency using HVSR},
  series = {Bulletin of the Seismological Society of America : BSSA},
  volume    = {110},
  journal   = {Bulletin of the Seismological Society of America : BSSA},
  number    = {2},
  publisher = {Seismological Society of America},
  address   = {El Cerito, Calif.},
  issn      = {0037-1106},
  doi       = {10.1785/0120190186},
  pages     = {427 -- 440},
  year      = {2020},
  abstract  = {In this investigation, we examine the uncertainties using the horizontal-to-vertical spectral ratio (HVSR) technique on earthquake recordings to detect site resonant frequencies at 207 KiK-net sites. Our results show that the scenario dependence of response (pseudospectral acceleration) spectral ratio could bias the estimates of resonant frequencies for sites having multiple significant peaks with comparable amplitudes. Thus, the Fourier amplitude spectrum (FAS) should be preferred in computing HVSR. For more than 80\% of the investigated sites, the first peak (in the frequency domain) on the average HVSR curve over multiple sites coincides with the highest peak. However, for sites with multiple peaks, the highest peak frequency (f(p)) is less susceptible to the selection criteria of significant peaks and the extent of smoothing to spectrum than the first peak frequency (f(0)). Meanwhile, in comparison to the surface-to-borehole spectral ratio, f(0) tends to underestimate the predominant frequency (at which the largest amplification occurs) more than f(p). In addition, in terms of characterizing linear site response, f(p) shows a better overall performance than f(0). Based on these findings, we thus recommend that seismic network operators provide f(p) on the average HVSRFAS curve as a priority, ideally together with the average HVSRFAS curve in site characterization.},
  language  = {en}
}
@article{TronickeAllroggenBiermannetal.2020,
  author    = {Tronicke, Jens and Allroggen, Niklas and Biermann, Felix and Fanselow, Florian and Guillemoteau, Julien and Krauskopf, Christof and L{\"u}ck, Erika},
  title     = {Rapid multiscale analysis of near-surface geophysical anomaly maps},
  series = {Geophysics},
  volume    = {85},
  journal   = {Geophysics},
  number    = {4},
  publisher = {Society of Exploration Geophysicists},
  address   = {Tulsa, Okla.},
  issn      = {0016-8033},
  doi       = {10.1190/GEO2019-0564.1},
  pages     = {B109 -- B118},
  year      = {2020},
  abstract  = {In near- surface geophysics, ground-based mapping surveys are routinely used in a variety of applications including those from archaeology, civil engineering, hydrology, and soil science. The resulting geophysical anomaly maps of, for example, magnetic or electrical parameters are usually interpreted to laterally delineate subsurface structures such as those related to the remains of past human activities, subsurface utilities and other installations, hydrological properties, or different soil types. To ease the interpretation of such data sets, we have developed a multiscale processing, analysis, and visualization strategy. Our approach relies on a discrete redundant wavelet transform (RWT) implemented using cubic-spline filters and the a trous algorithm, which allows to efficiently compute a multiscale decomposition of 2D data using a series of 1D convolutions. The basic idea of the approach is presented using a synthetic test image, whereas our archaeogeophysical case study from northeast Germany demonstrates its potential to analyze and process rather typical geophysical anomaly maps including magnetic and topographic data. Our vertical-gradient magnetic data show amplitude variations over several orders of magnitude, complex anomaly patterns at various spatial scales, and typical noise patterns, whereas our topographic data show a distinct hill structure superimposed by a microtopographic stripe pattern and random noise. Our results demonstrate that the RWT approach is capable to successfully separate these components and that selected wavelet planes can be scaled and combined so that the reconstructed images allow for a detailed, multiscale structural interpretation also using integrated visualizations of magnetic and topographic data. Because our analysis approach is straightforward to implement without laborious parameter testing and tuning, computationally efficient, and easily adaptable to other geophysical data sets, we believe that it can help to rapidly analyze and interpret different geophysical mapping data collected to address a variety of near-surface applications from engineering practice and research.},
  language  = {en}
}
@article{WolfPhamMatthewsetal.2020,
  author    = {Wolf, Sabina and Pham, My and Matthews, Nathanial and Bubeck, Philip},
  title     = {Understanding the implementation gap},
  series = {Climate \& development},
  volume    = {13},
  journal   = {Climate \& development},
  number    = {1},
  publisher = {Taylor \& Francis LTD},
  address   = {Abingdon},
  issn      = {1756-5529},
  doi       = {10.1080/17565529.2020.1724068},
  pages     = {81 -- 94},
  year      = {2020},
  abstract  = {In recent years, nature-based solutions are receiving increasing attention in the field of disaster risk reduction and climate change adaptation as inclusive, no regret approaches. Ecosystem-based adaptation (EbA) can mitigate the impacts of climate change, build resilience and tackle environmental degradation thereby supporting the targets set by the 2030 Agenda, the Paris Agreement and the Sendai Framework. Despite these benefits, EbA is still rarely implemented in practice. To better understand the barriers to implementation, this research examines policy-makers' perceptions of EbA, using an extended version of Protection Motivation Theory as an analytical framework. Through semi-structured interviews with policy-makers at regional and provincial level in Central Vietnam, it was found that EbA is generally considered a promising response option, mainly due to its multiple ecosystem-service benefits. The demand for EbA measures was largely driven by the perceived consequences of natural hazards and climate change. Insufficient perceived response efficacy and time-lags in effectiveness for disaster risk reduction were identified as key impediments for implementation. Pilot projects and capacity building on EbA are important means to overcome these perceptual barriers. This paper contributes to bridging the knowledge-gap on political decision-making regarding EbA and can, thereby, promote its mainstreaming into policy plans.},
  language  = {en}
}
@article{RoetzlerTimmerman2020,
  author    = {R{\"o}tzler, Jochen and Timmerman, Martin Jan},
  title     = {Geochronological and petrological constraints from the evolution in the Saxon Granulite Massif, Germany, on the Variscan continental collision orogeny},
  series = {Journal of metamorphic geology},
  volume    = {39},
  journal   = {Journal of metamorphic geology},
  number    = {1},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0263-4929},
  doi       = {10.1111/jmg.12559},
  pages     = {3 -- 38},
  year      = {2020},
  abstract  = {Controversy over the plate tectonic affinity and evolution of the Saxon granulites in a two- or multi-plate setting during inter- or intracontinental collision makes the Saxon Granulite Massif a key area for the understanding of the Palaeozoic Variscan orogeny. The massif is a large dome structure in which tectonic slivers of metapelite and metaophiolite units occur along a shear zone separating a diapir-like body of high-Pgranulite below from low-Pmetasedimentary rocks above. Each of the upper structural units records a different metamorphic evolution until its assembly with the exhuming granulite body. New age and petrologic data suggest that the metaophiolites developed from early Cambrian protoliths during high-Pamphibolite facies metamorphism in the mid- to late-Devonian and thermal overprinting by the exhuming hot granulite body in the early Carboniferous. A correlation of new Ar-Ar biotite ages with publishedP-T-tdata for the granulites implies that exhumation and cooling of the granulite body occurred at average rates of similar to 8 mm/year and similar to 80 degrees C/Ma, with a drop in exhumation rate from similar to 20 to similar to 2.5 mm/year and a slight rise in cooling rate between early and late stages of exhumation. A time lag ofc. 2 Ma between cooling through the closure temperatures for argon diffusion in hornblende and biotite indicates a cooling rate of 90 degrees C/Ma when all units had assembled into the massif. A two-plate model of the Variscan orogeny in which the above evolution is related to a short-lived intra-Gondwana subduction zone conflicts with the oceanic affinity of the metaophiolites and the timescale ofc. 50 Ma for the metamorphism. Alternative models focusing on the internal Variscan belt assume distinctly different material paths through the lower or upper crust for strikingly similar granulite massifs. An earlier proposed model of bilateral subduction below the internal Variscan belt may solve this problem.},
  language  = {en}
}
@article{ScharfSudoPracejusetal.2020,
  author    = {Scharf, Andreas and Sudo, Masafumi and Pracejus, Bernhard and Mattern, Frank and Callegari, Ivan and Bauer, Wilfried and Scharf, Katharina},
  title     = {Late Lutetian (Eocene) mafic intrusion into shallow marine platform deposits north of the Oman Mountains (Rusayl Embayment) and its tectonic significance},
  series = {Journal of African earth sciences},
  volume    = {170},
  journal   = {Journal of African earth sciences},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1464-343X},
  doi       = {10.1016/j.jafrearsci.2020.103941},
  pages     = {15},
  year      = {2020},
  abstract  = {A silica undersaturated alkali-olivine basanitic magma intruded the late Paleocene/early Eocene Jafnayn Formation near Muscat. Geochemical analyses indicate that a significant amount of host rock (limestone) was assimilated into the magma. We dated the basanite as 42.7 +/- 1.0 Ma (2 sigma error; late Lutetian), using the whole rock Ar-40/Ar-39 step-wise heating technique. Intrusion occurred in the hanging wall of a major regional extensional shear zone (Frontal Range Fault, FRF) bounding the northern margin of two domes within the Oman Mountains (Jabal Akhdar and Saih Hatat domes). Two shear intervals along the FRF have been documented. The first interval lasted immediately after emplacement of the Semail Ophiolite (latest Cretaceous-early Eocene) while the second and poorly constrained interval was assumed to have occurred during the Oligocene. The proximity of the basanite to the FRF suggests that magma used extensional faults for the upper part of its ascent path. Reactivated Permian rift faults of the Pangaea rift or other preexisting faults may have been used for the lower ascent part. We conclude that the basanite intrusion coincided with the onset of the second deformation interval along the FRF, because (1) the position of the basanite is near a dextral releasing bend, associated with the second shear interval, (2) the overlap of our Ar-40/Ar-39 age with the cooling curves for rocks from the nearby Jabal Akhdar Dome, and (3) the basanite postdates the first FRF deformation episode by > 10 Ma. Thus, the second interval along the FRF had started already during the late Lutetian and probably lasted into the Miocene.},
  language  = {en}
}
@article{WeatherillCotton2020,
  author    = {Weatherill, Graeme and Cotton, Fabrice Pierre},
  title     = {A ground motion logic tree for seismic hazard analysis in the stable cratonic region of Europe},
  series = {Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering},
  volume    = {18},
  journal   = {Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering},
  number    = {14},
  publisher = {Springer Science + Business Media B.V.},
  address   = {Dordrecht},
  issn      = {1570-761X},
  doi       = {10.1007/s10518-020-00940-x},
  pages     = {6119 -- 6148},
  year      = {2020},
  abstract  = {Regions of low seismicity present a particular challenge for probabilistic seismic hazard analysis when identifying suitable ground motion models (GMMs) and quantifying their epistemic uncertainty. The 2020 European Seismic Hazard Model adopts a scaled backbone approach to characterise this uncertainty for shallow seismicity in Europe, incorporating region-to-region source and attenuation variability based on European strong motion data. This approach, however, may not be suited to stable cratonic region of northeastern Europe (encompassing Finland, Sweden and the Baltic countries), where exploration of various global geophysical datasets reveals that its crustal properties are distinctly different from the rest of Europe, and are instead more closely represented by those of the Central and Eastern United States. Building upon the suite of models developed by the recent NGA East project, we construct a new scaled backbone ground motion model and calibrate its corresponding epistemic uncertainties. The resulting logic tree is shown to provide comparable hazard outcomes to the epistemic uncertainty modelling strategy adopted for the Eastern United States, despite the different approaches taken. Comparison with previous GMM selections for northeastern Europe, however, highlights key differences in short period accelerations resulting from new assumptions regarding the characteristics of the reference rock and its influence on site amplification.},
  language  = {en}
}
@article{ZhuPilzCotton2020,
  author    = {Zhu, Chuanbin and Pilz, Marco and Cotton, Fabrice Pierre},
  title     = {Evaluation of a novel application of earthquake HVSR in site-specific amplification estimation},
  series = {Soil dynamics and earthquake engineering},
  volume    = {139},
  journal   = {Soil dynamics and earthquake engineering},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0267-7261},
  doi       = {10.1016/j.soildyn.2020.106301},
  pages     = {14},
  year      = {2020},
  abstract  = {Ground response analyses (GRA) model the vertical propagations of SH waves through flat-layered media (1DSH) and are widely carried out to evaluate local site effects in practice. Horizontal-to-vertical spectral ratio (HVSR) technique is a cost-effective approach to extract certain site-specific information, e.g., site fundamental frequency (f(0)), but HVSR values cannot be directly used to approximate the levels of S-wave amplifications. Motivated by the work of Kawase et al. (2019), we propose a procedure to correct earthquake HVSR amplitudes for direct amplification estimations. The empirical correction compensates HVSR by generic vertical amplification spectra categorized by the vertical fundamental frequency (f(0v)) via kappa-means clustering. In this investigation, we evaluate the effectiveness of the corrected HVSR in approximating observed linear amplifications in comparison with 1DSH modellings. We select a total of 90 KiK-net (Kiban Kyoshin network) surface-downhole sites which are found to have no velocity contrasts below their boreholes and thus of which surface-to-borehole spectral ratios (SBSRs) can be taken as their empirical transfer functions (ETFs). 1DSH-based theoretical transfer functions (TTFs) are computed in the linear domain considering uncertainties in Vs profiles through randomizations. Five goodness-of-fit metrics are adopted to gauge the closeness between observed (ETF) and predicted (i.e., TTF and corrected HVSR) amplifications in both amplitude and spectral shape over frequencies from f(0) to 25 Hz. We find that the empirical correction to HVSR is highly effective and achieves a "good match" in both spectral shape and amplitude at the majority of the 90 KiK-net sites, as opposed to less than one-third for the 1DSH modelling. In addition, the empirical correction does not require a velocity model, which GRAs require, and thus has great potentials in seismic hazard assessments.},
  language  = {en}
}
@article{RiedlMelnickMibeietal.2020,
  author    = {Riedl, Simon and Melnick, Daniel and Mibei, Geoffrey K. and Njue, Lucy and Strecker, Manfred},
  title     = {Continental rifting at magmatic centres},
  series = {Journal of the geological society},
  volume    = {177},
  journal   = {Journal of the geological society},
  number    = {1},
  publisher = {Geological Soc. Publ. House},
  address   = {Bath},
  issn      = {0016-7649},
  doi       = {10.1144/jgs2019-021},
  pages     = {153 -- 169},
  year      = {2020},
  abstract  = {The structural evolution of calderas in rifts helps to characterize the spatiotemporal relationships between magmatism, long wavelength crustal deformation and the formation of tectonic deformation zones along the rift axis. We document the structural characteristics of the c. 36 ka old Menengai Caldera located within a young zone of extension in the central Kenya Rift. Field mapping and high-resolution digital surface models show that NNE-striking Holocene normal faults perpendicular to the regional ESE-WNWextension direction dominate the interior sectors of the rift. Inside the caldera, these structures are overprinted by post-collapse doming and faulting of the magmatic centre, resulting in obliquely slipping normal faults bounding a resurgence horst. Radiocarbon dating of faulted units as young as 5 ka cal BP and the palaeo-shorelines of a lake formed during the African Humid Period in the Nakuru Basin indicate that volcanism and fault activity inside and in the vicinity of Menengai must have been sustained during the Holocene. Our analysis confirms that the caldera is located at the centre of an extending rift segment and suggests that other magmatic centres and young zones of faulting along the volcano-tectonic axis of the Kenya Rift may constitute nucleation points of faulting that ultimately foster future continental break-up.},
  language  = {en}
}
@article{SchmidtHesseAttingeretal.2020,
  author    = {Schmidt, Lennart and Hesse, Falk and Attinger, Sabine and Kumar, Rohini},
  title     = {Challenges in applying machine learning models for hydrological inference},
  series = {Water resources research},
  volume    = {56},
  journal   = {Water resources research},
  number    = {5},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0043-1397},
  doi       = {10.1029/2019WR025924},
  pages     = {10},
  year      = {2020},
  abstract  = {Machine learning (ML) algorithms are being increasingly used in Earth and Environmental modeling studies owing to the ever-increasing availability of diverse data sets and computational resources as well as advancement in ML algorithms. Despite advances in their predictive accuracy, the usefulness of ML algorithms for inference remains elusive. In this study, we employ two popular ML algorithms, artificial neural networks and random forest, to analyze a large data set of flood events across Germany with the goals to analyze their predictive accuracy and their usability to provide insights to hydrologic system functioning. The results of the ML algorithms are contrasted against a parametric approach based on multiple linear regression. For analysis, we employ a model-agnostic framework named Permuted Feature Importance to derive the influence of models' predictors. This allows us to compare the results of different algorithms for the first time in the context of hydrology. Our main findings are that (1) the ML models achieve higher prediction accuracy than linear regression, (2) the results reflect basic hydrological principles, but (3) further inference is hindered by the heterogeneity of results across algorithms. Thus, we conclude that the problem of equifinality as known from classical hydrological modeling also exists for ML and severely hampers its potential for inference. To account for the observed problems, we propose that when employing ML for inference, this should be made by using multiple algorithms and multiple methods, of which the latter should be embedded in a cross-validation routine.},
  language  = {en}
}
@article{OttoKempka2020,
  author    = {Otto, Christopher and Kempka, Thomas},
  title     = {Synthesis gas composition prediction for underground coal gasification using a thermochemical equilibrium modeling approach},
  series = {Energies},
  volume    = {13},
  journal   = {Energies},
  number    = {5},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1996-1073},
  doi       = {10.3390/en13051171},
  pages     = {17},
  year      = {2020},
  abstract  = {Underground coal gasification (UCG) is an in situ conversion technique that enables the production of high-calorific synthesis gas from resources that are economically not minable by conventional methods. A broad range of end-use options is available for the synthesis gas, including fuels and chemical feedstock production. Furthermore, UCG also offers a high potential for integration with Carbon Capture and Storage (CCS) to mitigate greenhouse gas emissions. In the present study, a stoichiometric equilibrium model, based on minimization of the Gibbs function has been used to estimate the equilibrium composition of the synthesis gas. Thereto, we further developed and applied a proven thermodynamic equilibrium model to simulate the relevant thermochemical coal conversion processes (pyrolysis and gasification). Our modeling approach has been validated against thermodynamic models, laboratory gasification experiments and UCG field trial data reported in the literature. The synthesis gas compositions have been found to be in good agreement under a wide range of different operating conditions. Consequently, the presented modeling approach enables an efficient quantification of synthesis gas quality resulting from UCG, considering varying coal and oxidizer compositions at deposit-specific pressures and temperatures.},
  language  = {en}
}
@article{AllroggenBeiterTronicke2020,
  author    = {Allroggen, Niklas and Beiter, Daniel and Tronicke, Jens},
  title     = {Ground-penetrating radar monitoring of fast subsurface processes},
  series = {Geophysics},
  volume    = {85},
  journal   = {Geophysics},
  number    = {3},
  publisher = {Society of Exploration Geophysicists},
  address   = {Tulsa},
  issn      = {0016-8033},
  doi       = {10.1190/GEO2019-0737.1},
  pages     = {A19 -- A23},
  year      = {2020},
  abstract  = {Earth and environmental sciences rely on detailed information about subsurface processes. Whereas geophysical techniques typically provide highly resolved spatial images, monitoring subsurface processes is often associated with enormous effort and, therefore, is usually limited to point information in time or space. Thus, the development of spatial and temporal continuous field monitoring methods is a major challenge for the understanding of subsurface processes. We have developed a novel method for ground-penetrating-radar (GPR) reflection monitoring of subsurface flow processes under unsaturated conditions and applied it to a hydrological infiltration experiment performed across a periglacial slope deposit in northwest Luxembourg. Our approach relies on a spatial and temporal quasicontinuous data recording and processing, followed by an attribute analysis based on analyzing differences between individual time steps. The results demonstrate the ability of time-lapse GPR monitoring to visualize the spatial and temporal dynamics of preferential flow processes with a spatial resolution in the order of a few decimeters and temporal resolution in the order of a few minutes. We observe excellent agreement with water table information originating from different boreholes. This demonstrates the potential of surface-based GPR reflection monitoring to observe the spatiotemporal dynamics of water movements in the subsurface. It provides valuable, and so far not accessible, information for example in the field of hydrology and pedology that allows studying the actual subsurface processes rather than deducing them from point information.},
  language  = {en}
}
@article{RichterHainzlDahmetal.2020,
  author    = {Richter, Gudrun and Hainzl, Sebastian and Dahm, Torsten and Z{\"o}ller, Gert},
  title     = {Stress-based, statistical modeling of the induced seismicity at the Groningen gas field},
  series = {Environmental earth sciences},
  volume    = {79},
  journal   = {Environmental earth sciences},
  number    = {11},
  publisher = {Springer},
  address   = {New York},
  issn      = {1866-6280},
  doi       = {10.1007/s12665-020-08941-4},
  pages     = {15},
  year      = {2020},
  abstract  = {Groningen is the largest onshore gas field under production in Europe. The pressure depletion of the gas field started in 1963. In 1991, the first induced micro-earthquakes have been located at reservoir level with increasing rates in the following decades. Most of these events are of magnitude less than 2.0 and cannot be felt. However, maximum observed magnitudes continuously increased over the years until the largest, significant event with ML=3.6 was recorded in 2014, which finally led to the decision to reduce the production. This causal sequence displays the crucial role of understanding and modeling the relation between production and induced seismicity for economic planing and hazard assessment. Here we test whether the induced seismicity related to gas exploration can be modeled by the statistical response of fault networks with rate-and-state-dependent frictional behavior. We use the long and complete local seismic catalog and additionally detailed information on production-induced changes at the reservoir level to test different seismicity models. Both the changes of the fluid pressure and of the reservoir compaction are tested as input to approximate the Coulomb stress changes. We find that the rate-and-state model with a constant tectonic background seismicity rate can reproduce the observed long delay of the seismicity onset. In contrast, so-called Coulomb failure models with instantaneous earthquake nucleation need to assume that all faults are initially far from a critical state of stress to explain the delay. Our rate-and-state model based on the fluid pore pressure fits the spatiotemporal pattern of the seismicity best, where the fit further improves by taking the fault density and orientation into account. Despite its simplicity with only three free parameters, the rate-and-state model can reproduce the main statistical features of the observed activity.},
  language  = {en}
}
@article{ReinHannemannThomasetal.2020,
  author    = {Rein, Theresa and Hannemann, Katrin and Thomas, Christine and Korn, Michael},
  title     = {Location and characteristics of the X-discontinuity beneath SW Morocco and the adjacent shelf area using P-wave receiver functions},
  series = {Geophysical journal international},
  volume    = {223},
  journal   = {Geophysical journal international},
  number    = {3},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0956-540X},
  doi       = {10.1093/gji/ggaa379},
  pages     = {1780 -- 1793},
  year      = {2020},
  abstract  = {Receiver function approaches have proven to be valuable for the investigation of crustal and upper mantle discontinuities whose sharp changes in seismic velocities cause wave conversions. While the crustal and mantle transition zone discontinuities are largely understood, the X-discontinuity at 250-350 km depth is still an object of controversial debate. The origin and global distribution of this structure with a velocity jump of 1.5-4.8\% for compressional and shear waves is still unexplained. Although the crustal and mantle transition zone discontinuities beneath SW Morocco and surroundings have been investigated, only a few studies observed the X-discontinuity and place the depth at 260-370 km beneath the region of western Morocco. In order to better locate and characterize the X-discontinuity beneath southwest Morocco, we create P-wave receiver functions using data recorded by the Morocco-Munster array and detect the X-discontinuity at apparent depths of 285-350 km. In the western part of our study region we find apparent depths of similar to 310-340 km. The eastern part of the study area appears more complex: we locate two velocity jumps at apparent depths of around 285-295 km and 330-350 km in the northeast, and in the southeast we find a discontinuity at apparent depths of 340-350 km. Due to the large depth range and the twofold appearance of the X-discontinuity, we suggest that two different phase transitions cause the X-discontinuity beneath SW Morocco. The velocity contrasts at larger depths likely point to the coesite-stishovite phase transition occurring in deep eclogitic pools. The shallower depths can be explained by the transition from orthoenstatite to high-pressure clinoenstatite which requires the reaction between eclogite and peridotite to form orthopyroxene-rich peridotite. This reaction is likely related to previously proposed small-scale mantle upwellings beneath SW Morocco. Since both phase transitions require eclogite occurrence, the location of the X-discontinuity in this region can be used to indicate the location of recycled oceanic crust.},
  language  = {en}
}
@article{SakiMiriOberhaensli2020,
  author    = {Saki, Adel and Miri, Mirmohammad and Oberh{\"a}nsli, Roland},
  title     = {High temperature - low pressure metamorphism during subduction of Neo-Tethys beneath the Iranian plate},
  series = {Mineralogy and petrology},
  volume    = {114},
  journal   = {Mineralogy and petrology},
  number    = {6},
  publisher = {Springer},
  address   = {Wien [u.a.]},
  issn      = {0930-0708},
  doi       = {10.1007/s00710-020-00721-z},
  pages     = {539 -- 557},
  year      = {2020},
  abstract  = {Subduction of Neo-Tethys oceanic lithosphere beneath the Iranian plate during the Mesozoic formed several igneous bodies of ultramafic to intermediate and felsic composition. Intrusion of these magmas into a regional metamorphic sequence (the Sanandaj-Sirjan Zone) caused partial melting and formation of migmatites with meta-pelitic protoliths. The Alvand complex (west Iran) is a unique area comprising migmatites of both mafic and pelitic protoliths. In this area, the gabbroic rocks contain veins of leucosome at their contact with pyroxenite and olivine gabbro. These leucosomes are geochemically and mineralogically different from leucosomes of the meta-pelitic migmatites and clearly show properties of I-type granites. Microscopic observations and whole rock compositions of the mafic migmatite leucosomes show that migmatization occurred through partial melting of biotite, hornblende and plagioclase. Thermobarometric calculations indicate 800 degrees C and 3.7 kbar for partial melting, although phase diagram modeling demonstrates that the presence of water could decrease the solidus temperature by about 40 degrees C. Our results suggest an asthenospheric magma upwelling as the source of heat for partial melting of the gabbroic rock during subduction of Neo-Tethys oceanic crust under the western edge of the Iranian plate. The present study also reveals relationships between migmatization and formation of S- and I -type granites in the area.},
  language  = {en}
}
@article{WeissWaltersMorishitaetal.2020,
  author    = {Weiss, Jonathan R. and Walters, Richard J. and Morishita, Yu and Wright, Tim J. and Lazecky, Milan and Wang, Hua and Hussain, Ekbal and Hooper, Andrew J. and Elliott, John R. and Rollins, Chris and Yu, Chen and Gonzalez, Pablo J. and Spaans, Karsten and Li, Zhenhong and Parsons, Barry},
  title     = {High-resolution surface velocities and strain for Anatolia from Sentinel-1 InSAR and GNSS data},
  series = {Geophysical research letters},
  volume    = {47},
  journal   = {Geophysical research letters},
  number    = {17},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0094-8276},
  doi       = {10.1029/2020GL087376},
  pages     = {12},
  year      = {2020},
  abstract  = {Measurements of present-day surface deformation are essential for the assessment of long-term seismic hazard. The European Space Agency's Sentinel-1 satellites enable global, high-resolution observation of crustal motion from Interferometric Synthetic Aperture Radar (InSAR). We have developed automated InSAR processing systems that exploit the first similar to 5 years of Sentinel-1 data to measure surface motions for the similar to 800,000-km(2) Anatolian region. Our new 3-D velocity and strain rate fields illuminate deformation patterns dominated by westward motion of Anatolia relative to Eurasia, localized strain accumulation along the North and East Anatolian Faults, and rapid vertical signals associated with anthropogenic activities and to a lesser extent extension across the grabens of western Anatolia. We show that automatically processed Sentinel-1 InSAR data can characterize details of the velocity and strain rate fields with high resolution and accuracy over large regions. These results are important for assessing the relationship between strain accumulation and release in earthquakes. <br /> Plain Language Summary Satellite-based measurements of small rates of motion of the Earth's surface made at high spatial resolutions and over large areas are important for many geophysical applications including improving earthquake hazard models. We take advantage of recent advances in geodetic techniques in order to measure surface velocities and tectonic strain accumulation across the Anatolia region, including the highly seismogenic and often deadly North Anatolian Fault. We show that by combining Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) data with Global Navigation Satellite System (GNSS) measurements we can enhance our view of surface deformation associated with active tectonics, the earthquake cycle, and anthropogenic processes.},
  language  = {en}
}
@article{BaroniFrancke2020,
  author    = {Baroni, Gabriele and Francke, Till},
  title     = {An effective strategy for combining variance- and distribution-based global sensitivity analysis},
  series = {Environmental modelling \& software with environment data news},
  volume    = {134},
  journal   = {Environmental modelling \& software with environment data news},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1364-8152},
  doi       = {10.1016/j.envsoft.2020.104851},
  pages     = {14},
  year      = {2020},
  abstract  = {We present a new strategy for performing global sensitivity analysis capable to estimate main and interaction effects from a generic sampling design. The new strategy is based on a meaningful combination of varianceand distribution-based approaches. The strategy is tested on four analytic functions and on a hydrological model. Results show that the analysis is consistent with the state-of-the-art Saltelli/Jansen formula but to better quantify the interaction effect between the input factors when the output distribution is skewed. Moreover, the estimation of the sensitivity indices is much more robust requiring a smaller number of simulations runs. Specific settings and alternative methods that can be integrated in the new strategy are also discussed. Overall, the strategy is considered as a new simple and effective tool for performing global sensitivity analysis that can be easily integrated in any environmental modelling framework.},
  language  = {en}
}
@article{ZiemannMadariaga2020,
  author    = {Ziemann, Martin Andreas and Madariaga, Juan Manuel},
  title     = {Applications of Raman spectroscopy in art and archaeology},
  series = {Journal of Raman spectroscopy},
  volume    = {52},
  journal   = {Journal of Raman spectroscopy},
  number    = {1},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0377-0486},
  doi       = {10.1002/jrs.6054},
  pages     = {8 -- 14},
  year      = {2020},
  abstract  = {The 10th edition of the International Congress on the Application of Raman Spectroscopy in Art and Archaeology (RAA2019) was held in Potsdam (Germany) from 3 to 7 September 2019, with eight keynote lectures, 35 oral presentations and 18 Poster Presentations. The number of active participants was 68 delegates from 20 countries among the 236 authors that presented at least one work.},
  language  = {en}
}
@article{MorgensternOverduinGuentheretal.2020,
  author    = {Morgenstern, Anne and Overduin, Pier Paul and G{\"u}nther, Frank and Stettner, Samuel and Ramage, Justine and Schirrmeister, Lutz and Grigoriev, Mikhail N. and Grosse, Guido},
  title     = {Thermo-erosional valleys in Siberian ice-rich permafrost},
  series = {Permafrost and Periglacial Processes},
  volume    = {32},
  journal   = {Permafrost and Periglacial Processes},
  number    = {1},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {1045-6740},
  doi       = {10.1002/ppp.2087},
  pages     = {59 -- 75},
  year      = {2020},
  abstract  = {Thermal erosion is a major mechanism of permafrost degradation, resulting in characteristic landforms. We inventory thermo-erosional valleys in ice-rich coastal lowlands adjacent to the Siberian Laptev Sea based on remote sensing, Geographic Information System (GIS), and field investigations for a first regional assessment of their spatial distribution and characteristics. Three study areas with similar geological (Yedoma Ice Complex) but diverse geomorphological conditions vary in valley areal extent, incision depth, and branching geometry. The most extensive valley networks are incised deeply (up to 35 m) into the broad inclined lowland around Mamontov Klyk. The flat, low-lying plain forming the Buor Khaya Peninsula is more degraded by thermokarst and characterized by long valleys of lower depth with short tributaries. Small, isolated Yedoma Ice Complex remnants in the Lena River Delta predominantly exhibit shorter but deep valleys. Based on these hydrographical network and topography assessments, we discuss geomorphological and hydrological connections to erosion processes. Relative catchment size along with regional slope interact with other Holocene relief-forming processes such as thermokarst and neotectonics. Our findings suggest that thermo-erosional valleys are prominent, hitherto overlooked permafrost degradation landforms that add to impacts on biogeochemical cycling, sediment transport, and hydrology in the degrading Siberian Yedoma Ice Complex.},
  language  = {en}
}
@article{Oberhaensli2020,
  author    = {Oberh{\"a}nsli, Roland},
  title     = {Deep-time Digital Earth (DDE) the first IUGS big science program},
  series = {Journal of the Geological Society of India},
  volume    = {95},
  journal   = {Journal of the Geological Society of India},
  number    = {3},
  publisher = {Springer India},
  address   = {New Delhi},
  issn      = {0016-7622},
  doi       = {10.1007/s12594-020-1420-5},
  pages     = {223 -- 226},
  year      = {2020},
  language  = {en}
}
@article{SteinbergSudhausHeimannetal.2020,
  author    = {Steinberg, Andreas and Sudhaus, Henriette and Heimann, Sebastian and Kr{\"u}ger, Frank},
  title     = {Sensitivity of InSAR and teleseismic observations to earthquake rupture segmentation},
  series = {Geophysical journal international},
  volume    = {223},
  journal   = {Geophysical journal international},
  number    = {2},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0956-540X},
  doi       = {10.1093/gji/ggaa351},
  pages     = {875 -- 907},
  year      = {2020},
  abstract  = {Earthquakes often rupture across more than one fault segment. If such rupture segmentation occurs on a significant scale, a simple point-source or one-fault model may not represent the rupture process well. As a consequence earthquake characteristics inferred, based on one-source assumptions, may become systematically wrong. This might have effects on follow-up analyses, for example regional stress field inversions and seismic hazard assessments. While rupture segmentation is evident for most M-w > 7 earthquakes, also smaller ones with 5.5 < M-w < 7 can be segmented. We investigate the sensitivity of globally available data sets to rupture segmentation and their resolution to reliably estimate the mechanisms in presence of segmentation. We focus on the sensitivity of InSAR (Interferometric Synthetic Aperture Radar) data in the static near-field and seismic waveforms in the far-field of the rupture and carry out non-linear and Bayesian optimizations of single-source and two-sources kinematic models (double-couple point sources and finite, rectangular sources) using InSAR and teleseismic waveforms separately. Our case studies comprises of four M-w 6-7 earthquakes: the 2009 L'Aquila and 2016 Amatrice (Italy) and the 2005 and 2008 Zhongba (Tibet) earthquakes. We contrast the data misfits of different source complexity by using the Akaike informational criterion (AIC). We find that the AIC method is well suited for data-driven inferences on significant rupture segmentation for the given data sets. This is based on our observation that an AIC-stated significant improvement of data fit for two-segment models over one-segment models correlates with significantly different mechanisms of the two source segments and their average compared to the single-segment mechanism. We attribute these modelled differences to a sufficient sensitivity of the data to resolve rupture segmentation. Our results show that near-field data are generally more sensitive to rupture segmentation of shallow earthquakes than far-field data but that also teleseismic data can resolve rupture segmentation in the studied magnitude range. We further conclude that a significant difference in the modelled source mechanisms for different segmentations shows that an appropriate choice of model segmentation matters for a robust estimation of source mechanisms. It reduces systematic biases and trade-off and thereby improves the knowledge on the rupture. Our study presents a strategy and method to detect significant rupture segmentation such that an appropriate model complexity can be used in the source mechanism inference. A similar, systematic investigation of earthquakes in the range of M-w 5.5-7 could provide important hazard-relevant statistics on rupture segmentation. In these cases single-source models introduce a systematic bias. Consideration of rupture segmentation therefore matters for a robust estimation of source mechanisms of the studied earthquakes.},
  language  = {en}
}
@article{PilzCottonRazafindrakotoetal.2020,
  author    = {Pilz, Marco and Cotton, Fabrice Pierre and Razafindrakoto, Hoby Njara Tendrisoa and Weatherill, Graeme and Spies, Thomas},
  title     = {Regional broad-band ground-shaking modelling over extended and thick sedimentary basins},
  series = {Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering},
  volume    = {19},
  journal   = {Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering},
  number    = {2},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {1570-761X},
  doi       = {10.1007/s10518-020-01004-w},
  pages     = {581 -- 603},
  year      = {2020},
  abstract  = {The simulation of broad-band (0.1 to 10 + Hz) ground-shaking over deep and spatially extended sedimentary basins at regional scales is challenging. We evaluate the ground-shaking of a potential M 6.5 earthquake in the southern Lower Rhine Embayment, one of the most important areas of earthquake recurrence north of the Alps, close to the city of Cologne in Germany. In a first step, information from geological investigations, seismic experiments and boreholes is combined for deriving a harmonized 3D velocity and attenuation model of the sedimentary layers. Three alternative approaches are then applied and compared to evaluate the impact of the sedimentary cover on ground-motion amplification. The first approach builds on existing response spectra ground-motion models whose amplification factors empirically take into account the influence of the sedimentary layers through a standard parameterization. In the second approach, site-specific 1D amplification functions are computed from the 3D basin model. Using a random vibration theory approach, we adjust the empirical response spectra predicted for soft rock conditions by local site amplification factors: amplifications and associated ground-motions are predicted both in the Fourier and in the response spectra domain. In the third approach, hybrid physics-based ground-motion simulations are used to predict time histories for soft rock conditions which are subsequently modified using the 1D site-specific amplification functions computed in method 2. For large distances and at short periods, the differences between the three approaches become less notable due to the significant attenuation of the sedimentary layers. At intermediate and long periods, generic empirical ground-motion models provide lower levels of amplification from sedimentary soils compared to methods taking into account site-specific 1D amplification functions. In the near-source region, hybrid physics-based ground-motions models illustrate the potentially large variability of ground-motion due to finite source effects.},
  language  = {en}
}
@article{BalischewskiBehrensZehbeetal.2020,
  author    = {Balischewski, Christian and Behrens, Karsten and Zehbe, Kerstin and G{\"u}nter, Christina and Mies, Stefan and Sperlich, Eric and Kelling, Alexandra and Taubert, Andreas},
  title     = {Ionic liquids with more than one metal},
  series = {Chemistry - a European journal},
  volume    = {26},
  journal   = {Chemistry - a European journal},
  number    = {72},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0947-6539},
  doi       = {10.1002/chem.202003097},
  pages     = {17504 -- 17513},
  year      = {2020},
  abstract  = {Thirteen N-butylpyridinium salts, including three monometallic [C4Py](2)[MCl4], nine bimetallic [C4Py](2)[(M1-xMxCl4)-M-a-Cl-b] and one trimetallic compound [C4Py](2)[(M1-y-zMyMz (c) Cl4)-M-a-M-b] (M=Co, Cu, Mn; x=0.25, 0.50 or 0.75 and y=z=0.33), were synthesized and their structure and thermal and electrochemical properties were studied. All compounds are ionic liquids (ILs) with melting points between 69 and 93 degrees C. X-ray diffraction proves that all ILs are isostructural. The conductivity at room temperature is between 10(-4) and 10(-8) S cm(-1). Some Cu-based ILs reach conductivities of 10(-2) S cm(-1), which is, however, probably due to IL dec. This correlates with the optical bandgap measurements indicating the formation of large bandgap semiconductors. At elevated temperatures approaching the melting points, the conductivities reach up to 1.47x10(-1) S cm(-1) at 70 degrees C. The electrochemical stability windows of the ILs are between 2.5 and 3.0 V.},
  language  = {en}
}
@article{KloseChaparroSchillingetal.2020,
  author    = {Klose, Tim and Chaparro, M. Carme and Schilling, Frank and Butscher, Christoph and Klumbach, Steffen and Blum, Philipp},
  title     = {Fluid flow simulations of a large-scale borehole leakage experiment},
  series = {Transport in Porous Media},
  volume    = {136},
  journal   = {Transport in Porous Media},
  number    = {1},
  publisher = {Springer},
  address   = {New York},
  issn      = {0169-3913},
  doi       = {10.1007/s11242-020-01504-y},
  pages     = {125 -- 145},
  year      = {2020},
  abstract  = {Borehole leakage is a common and complex issue. Understanding the fluid flow characteristics of a cemented area inside a borehole is crucial to monitor and quantify the wellbore integrity as well as to find solutions to minimise existing leakages. In order to improve our understanding of the flow behaviour of cemented boreholes, we investigated experimental data of a large-scale borehole leakage tests by means of numerical modelling using three different conceptual models. The experiment was performed with an autoclave system consisting of two vessels bridged by a cement-filled casing. After a partial bleed-off at the well-head, a sustained casing pressure was observed due to fluid flow through the cementsteel composite. The aim of our simulations is to investigate and quantify the permeability of the cement-steel composite. From our model results, we conclude that the flow occurred along a preferential flow path at the cement-steel interface. Thus, the inner part of the cement core was impermeable during the duration of the experiment. The preferential flow path can be described as a highly permeable and highly porous area with an aperture of about 5 mu m and a permeability of 3 . 10(-12) m(2) (3 Darcy). It follows that the fluid flow characteristics of a cemented area inside a borehole cannot be described using one permeability value for the entire cement-steel composite. Furthermore, it can be concluded that the quality of the cement and the filling process regarding the cement-steel interface is crucial to minimize possible well leakages.},
  language  = {en}
}
@article{SamprognaMohorHudsonThieken2020,
  author    = {Samprogna Mohor, Guilherme and Hudson, Paul and Thieken, Annegret},
  title     = {A comparison of factors driving flood losses in households affected by different flood types},
  series = {Water resources research},
  volume    = {56},
  journal   = {Water resources research},
  number    = {4},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0043-1397},
  doi       = {10.1029/2019WR025943},
  pages     = {20},
  year      = {2020},
  abstract  = {Flood loss data collection and modeling are not standardized, and previous work has indicated that losses from different flood types (e.g., riverine and groundwater) may follow different driving forces. However, different flood types may occur within a single flood event, which is known as a compound flood event. Therefore, we aimed to identify statistical similarities between loss-driving factors across flood types and test whether the corresponding losses should be modeled separately. In this study, we used empirical data from 4,418 respondents from four survey campaigns studying households in Germany that experienced flooding. These surveys sought to investigate several features of the impact process (hazard, socioeconomic, preparedness, and building characteristics, as well as flood type). While the level of most of these features differed across flood type subsamples (e.g., degree of preparedness), they did so in a nonregular pattern. A variable selection process indicates that besides hazard and building characteristics, information on property-level preparedness was also selected as a relevant predictor of the loss ratio. These variables represent information, which is rarely adopted in loss modeling. Models shall be refined with further data collection and other statistical methods. To save costs, data collection efforts should be steered toward the most relevant predictors to enhance data availability and increase the statistical power of results. Understanding that losses from different flood types are driven by different factors is a crucial step toward targeted data collection and model development and will finally clarify conditions that allow us to transfer loss models in space and time. <br /> Key Points <br /> Survey data of flood-affected households show different concurrent flood types, undermining the use of a single-flood-type loss model Thirteen variables addressing flood hazard, the building, and property level preparedness are significant predictors of the building loss ratio Flood type-specific models show varying significance across the predictor variables, indicating a hindrance to model transferability},
  language  = {en}
}
@article{WangKwiatekRybackietal.2020,
  author    = {Wang, Lei and Kwiatek, Grzegorz and Rybacki, Erik and Bohnhoff, Marco and Dresen, Georg},
  title     = {Injection-induced seismic moment release and laboratory fault slip},
  series = {Geophysical research letters},
  volume    = {47},
  journal   = {Geophysical research letters},
  number    = {22},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0094-8276},
  doi       = {10.1029/2020GL089576},
  pages     = {11},
  year      = {2020},
  abstract  = {Understanding the relation between injection-induced seismic moment release and operational parameters is crucial for early identification of possible seismic hazards associated with fluid-injection projects. We conducted laboratory fluid-injection experiments on permeable sandstone samples containing a critically stressed fault at different fluid pressurization rates. The observed fluid-induced fault deformation is dominantly aseismic. Fluid-induced stick-slip and fault creep reveal that total seismic moment release of acoustic emission (AE) events is related to total injected volume, independent of respective fault slip behavior. Seismic moment release rate of AE scales with measured fault slip velocity. For injection-induced fault slip in a homogeneous pressurized region, released moment shows a linear scaling with injected volume for stable slip (steady slip and fault creep), while we find a cubic relation for dynamic slip. Our results highlight that monitoring evolution of seismic moment release with injected volume in some cases may assist in discriminating between stable slip and unstable runaway ruptures.},
  language  = {en}
}
@article{MtilatilaBronstertBuergeretal.2020,
  author    = {Mtilatila, Lucy Mphatso Ng'ombe and Bronstert, Axel and B{\"u}rger, Gerd and Vormoor, Klaus Josef},
  title     = {Meteorological and hydrological drought assessment in Lake Malawi and Shire River basins (1970-2013)},
  series = {Hydrological sciences journal = Journal des sciences hydrologiques},
  volume    = {65},
  journal   = {Hydrological sciences journal = Journal des sciences hydrologiques},
  number    = {16},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {0262-6667},
  doi       = {10.1080/02626667.2020.1837384},
  pages     = {2750 -- 2764},
  year      = {2020},
  abstract  = {The study assesses the variability and trends of both meteorological and hydrological droughts from 1970 to 2013 in Lake Malawi and Shire River basins using the standardized precipitation index (SPI) and standardized precipitation and evaporation index (SPEI) for meteorological droughts and the lake level change index (LLCI) for hydrological droughts. Trends and slopes in droughts and drought drivers are estimated using Mann-Kendall test and Sen's slope, respectively. Results suggest that meteorological droughts are increasing due to a decrease in precipitation which is exacerbated by an increase in temperature (potential evapotranspiration). The hydrological system of Lake Malawi seems to have a >24-month memory towards meteorological conditions, since the 36-month SPEI can predict hydrological droughts 10 months in advance. The study has found the critical lake level that would trigger hydrological drought to be 474.1 m a.s.l. The increase in drought is a concern as this will have serious impacts on water resources and hydropower supply in Malawi.},
  language  = {en}
}
@article{Streck2020,
  author    = {Streck, Charlotte},
  title     = {Filling in for Governments?},
  series = {Journal for European Environmental \& Planning Law},
  volume    = {17},
  journal   = {Journal for European Environmental \& Planning Law},
  number    = {1},
  publisher = {Martinus Nijhoff Pub},
  address   = {Leiden},
  issn      = {1613-7272},
  doi       = {10.1163/18760104-01701003},
  pages     = {5 -- 28},
  year      = {2020},
  abstract  = {The 2015 Paris Agreement on climate change abandons the Kyoto Protocol's paradigm of binding emissions targets and relies instead on countries' voluntary contributions. However, the Paris Agreement encourages not only governments but also sub-national governments, corporations and civil society to contribute to reaching ambitious climate goals. In a transition from the regulated architecture of the Kyoto Protocol to the open system of the Paris Agreement, the Agreement seeks to integrate non-state actors into the treaty-based climate regime. In 2014 the secretariat of the United Nations Framework Convention on Climate Change Peru and France created the Non-State Actor Zone for Climate Action (and launched the Global Climate Action portal). In December 2019, this portal recorded more than twenty thousand climate-commitments of private and public non-state entities, making the non-state venues of international climate meetings decisively more exciting than the formal negotiation space. This level engagement and governments' response to it raises a flurry of questions in relation to the evolving nature of the climate regime and climate change governance, including the role of private actors as standard setters and the lack of accountability mechanisms for non-state actions. This paper takes these developments as occasion to discuss the changing role of private actors in the climate regime.},
  language  = {en}
}
@article{KoyanTronicke2020,
  author    = {Koyan, Philipp and Tronicke, Jens},
  title     = {3D modeling of ground-penetrating radar data across a realistic sedimentary model},
  series = {Computers \& geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology},
  volume    = {137},
  journal   = {Computers \& geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0098-3004},
  doi       = {10.1016/j.cageo.2020.104422},
  pages     = {9},
  year      = {2020},
  abstract  = {Ground-penetrating radar (GPR) is an established geophysical tool to explore a wide range of near-surface environments. Today, the use of synthetic GPR data is largely limited to 2D because 3D modeling is computationally more expensive. In fact, only recent developments of modeling tools and powerful hardware allow for a time-efficient computation of extensive 3D data sets. Thus, 3D subsurface models and resulting GPR data sets, which are of great interest to develop and evaluate novel approaches in data analysis and interpretation, have not been made publicly available up to now. <br /> We use a published hydrofacies data set of an aquifer-analog study within fluvio-glacial deposits to infer a realistic 3D porosity model showing heterogeneities at multiple spatial scales. Assuming fresh-water saturated sediments, we generate synthetic 3D GPR data across this model using novel GPU-acceleration included in the open-source software gprMax. We present a numerical approach to examine 3D wave-propagation effects in modeled GPR data. Using the results of this examination study, we conduct a spatial model decomposition to enable a computationally efficient 3D simulation of a typical GPR reflection data set across the entire model surface. We process the resulting GPR data set using a standard 3D structural imaging sequence and compare the results to selected input data to demonstrate the feasibility and potential of the presented modeling studies. We conclude on conceivable applications of our 3D GPR reflection data set and the underlying porosity model, which are both publicly available and, thus, can support future methodological developments in GPR and other near-surface geophysical techniques.},
  language  = {en}
}
@article{Hudson2020,
  author    = {Hudson, Paul},
  title     = {The affordability of flood risk property-level adaptation measures},
  series = {Risk Analysis},
  volume    = {40},
  journal   = {Risk Analysis},
  number    = {6},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0272-4332},
  doi       = {10.1111/risa.13465},
  pages     = {1151 -- 1167},
  year      = {2020},
  abstract  = {The affordability of property-level adaptation measures against flooding is crucial due to the movement toward integrated flood risk management, which requires the individuals threatened by flooding to actively manage flooding. It is surprising to find that affordability is not often discussed, given the important roles that affordability and social justice play regarding flood risk management. This article provides a starting point for investigating the potential rate of unaffordability of flood risk property-level adaptation measures across Europe using two definitions of affordability, which are combined with two different affordability thresholds from within flood risk research. It uses concepts of investment and payment affordability, with affordability thresholds based on residual income and expenditure definitions of unaffordability. These concepts, in turn, are linked with social justice through fairness concerns, in that, all should have equal capability to act, of which affordability is one avenue. In doing so, it was found that, for a large proportion of Europe, property owners generally cannot afford to make one-time payment of the cost of protective measures. These can be made affordable with installment payment mechanisms or similar mechanisms that spread costs over time. Therefore, the movement toward greater obligations for flood-prone residents to actively adapt to flooding should be accompanied by socially accessible financing mechanisms.},
  language  = {en}
}
@article{CrisologoHeistermann2020,
  author    = {Crisologo, Irene and Heistermann, Maik},
  title     = {Using ground radar overlaps to verify the retrieval of calibration bias estimates from spaceborne platforms},
  series = {Atmospheric measurement techniques : an interactive open access journal of the European Geosciences Union},
  volume    = {13},
  journal   = {Atmospheric measurement techniques : an interactive open access journal of the European Geosciences Union},
  number    = {2},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1867-1381},
  doi       = {10.5194/amt-13-645-2020},
  pages     = {645 -- 659},
  year      = {2020},
  abstract  = {Many institutions struggle to tap into the potential of their large archives of radar reflectivity: these data are often affected by miscalibration, yet the bias is typically unknown and temporally volatile. Still, relative calibration techniques can be used to correct the measurements a posteriori. For that purpose, the usage of spaceborne reflectivity observations from the Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) platforms has become increasingly popular: the calibration bias of a ground radar (GR) is estimated from its average reflectivity difference to the spaceborne radar (SR). Recently, Crisologo et al. (2018) introduced a formal procedure to enhance the reliability of such estimates: each match between SR and GR observations is assigned a quality index, and the calibration bias is inferred as a quality-weighted average of the differences between SR and GR. The relevance of quality was exemplified for the Subic S-band radar in the Philippines, which is greatly affected by partial beam blockage. The present study extends the concept of quality-weighted averaging by accounting for path-integrated attenuation (PIA) in addition to beam blockage. This extension becomes vital for radars that operate at the C or X band. Correspondingly, the study setup includes a C-band radar that substantially overlaps with the S-band radar. Based on the extended quality-weighting approach, we retrieve, for each of the two ground radars, a time series of calibration bias estimates from suitable SR overpasses. As a result of applying these estimates to correct the ground radar observations, the consistency between the ground radars in the region of overlap increased substantially. Furthermore, we investigated if the bias estimates can be interpolated in time, so that ground radar observations can be corrected even in the absence of prompt SR overpasses. We found that a moving average approach was most suitable for that purpose, although limited by the absence of explicit records of radar maintenance operations.},
  language  = {en}
}
@article{BrunelloAndermannMarcetal.2020,
  author    = {Brunello, Camilla Francesca and Andermann, Christoff and Marc, Odin and Schneider, Katharina A. and Comiti, Francesco and Achleitner, Stefan and Hovius, Niels},
  title     = {Annually resolved monsoon onset and withdrawal dates across the Himalayas derived from local precipitation statistics},
  series = {Geophysical research letters},
  volume    = {47},
  journal   = {Geophysical research letters},
  number    = {23},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0094-8276},
  doi       = {10.1029/2020GL088420},
  pages     = {12},
  year      = {2020},
  abstract  = {A local and flexible definition of the monsoon season based on hydrological evidence is important for the understanding and management of Himalayan water resources. Here, we present an objective statistical method to retrieve seasonal hydrometeorological transitions. Applied to daily rainfall data (1951-2015), this method shows an average longitudinal delay of similar to 15 days, with later monsoon onset and earlier withdrawal in the western Himalaya, consistent with the continental progression of wet air masses. This delay leads to seasons of different length along the Himalaya and biased precipitation amounts when using uniform calendric monsoon boundaries. In the Central Himalaya annual precipitation has increased, due primarily to an increase of premonsoon precipitation. These findings highlight issues associated with a static definition of monsoon boundaries and call for a deeper understanding of nonmonsoonal precipitation over the Himalayan water tower. <br /> Plain Language Summary Precipitation in the Himalayas determines water availability for the Indian foreland with large socioeconomic implications. Despite its importance, spatial and temporal patterns of precipitation are poorly understood. Here, we estimate the long-term average and trends of seasonal precipitation at the scale of individual catchments draining the Himalayas. We apply a statistical method to detect the timing of hydrometeorological seasons from local precipitation measurements, focusing on monsoon onset and withdrawal. We identify longitudinal and latitudinal delays, resulting in seasons of different length along and across the Himalayas. These spatial patterns and the annual variability of the monsoon boundaries mean that oft-used, fixed calendric dates, for example, 1 June to 30 September, may be inadequate for retrieving monsoon rainfall totals. Moreover, we find that, despite its prominent contribution to annual rainfall totals, the Indian summer monsoon cannot explain the increase of the annual precipitation over the Central Himalayas. Instead, this appears to be mostly driven by changes in premonsoon and winter rainfall. So far, little attention has been paid to premonsoon precipitation, but governed by evaporative processes and surface water availability, it may be enhanced by irrigation and changed land use in the Gangetic foreland.},
  language  = {en}
}
@article{FernandezPalominoHattermannKrysanovaetal.2020,
  author    = {Fernandez-Palomino, Carlos Antonio and Hattermann, Fred F. and Krysanova, Valentina and Vega-Jacome, Fiorella and Bronstert, Axel},
  title     = {Towards a more consistent eco-hydrological modelling through multi-objective calibration},
  series = {Hydrological sciences journal = Journal des sciences hydrologiques},
  volume    = {66},
  journal   = {Hydrological sciences journal = Journal des sciences hydrologiques},
  number    = {1},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {0262-6667},
  doi       = {10.1080/02626667.2020.1846740},
  pages     = {59 -- 74},
  year      = {2020},
  abstract  = {Most hydrological studies rely on a model calibrated using discharge alone. However, judging the model reliability based on such calibration is problematic, as it does not guarantee the correct representation of internal hydrological processes. This study aims (a) to develop a comprehensive multi-objective calibration framework using remote sensing vegetation data and hydrological signatures (flow duration curve - FDC, and baseflow index) in addition to discharge, and (b) to apply this framework for calibration of the Soil and Water Assessment Tool (SWAT) in a typical Andean catchment. Overall, our calibration approach outperformed traditional discharge-based and FDC signature-based calibration strategies in terms of vegetation, streamflow, and flow partitioning simulation. New hydrological insights for the region are the following: baseflow is the main component of the streamflow sustaining the long dry-season flow, and pasture areas offer higher water yield and baseflow than other land-cover types. The proposed approach could be used in other data-scarce regions with complex topography.},
  language  = {en}
}
@article{OlenBookhagen2020,
  author    = {Olen, Stephanie M. and Bookhagen, Bodo},
  title     = {Applications of SAR interferometric coherence time series},
  series = {Journal of geophysical research : Earth surface},
  volume    = {125},
  journal   = {Journal of geophysical research : Earth surface},
  number    = {3},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-9003},
  doi       = {10.1029/2019JF005141},
  pages     = {22},
  year      = {2020},
  abstract  = {Sediment transport domains in mountain landscapes are characterized by fundamentally different processes and rates depending on several factors, including geology, climate, and biota. Accurately identifying where transitions between transport domains occur is an important step to quantify the past, present, and future contribution of varying erosion and sedimentation processes and enhance our predictive capabilities. We propose a new methodology based on time series of synthetic aperture radar (SAR) interferometric coherence images to map sediment transport regimes across arid and semiarid landscapes. Using 4 years of Sentinel-1 data, we analyze sediment transport regimes for the south-central Andes in northwestern Argentina characterized by steep topographic and climatic gradients. We observe seasonally low coherence during the regional wet season, particularly on hillslopes and in alluvial channels. The spatial distribution of coherence is compared to drainage areas extracted from digital topography to identify two distinct transitions within watersheds: (a) a hillslope-to-fluvial and (b) a fluvial-to-alluvial transition. While transitions within a given basin can be well-constrained, the relative role of each sediment transport domain varies widely over the climatic and topographic gradients. In semiarid regions, we observe larger relative contributions from hillslopes compared to arid regions. Across regional gradients, the range of coherence within basins positively correlates to previously published millennial catchment-wide erosion rates and to topographic metrics used to indicate long-term uplift. Our study suggests that a dense time series of interferometric coherence can be used as a proxy for surface sediment movement and landscape stability in vegetation-free settings at event to decadal timescales.},
  language  = {en}
}
@article{GovinvanderBeekNajmanetal.2020,
  author    = {Govin, Gwladys and van der Beek, Peter and Najman, Yani and Millar, Ian and Gemignani, Lorenzo and Huyghe, Pascale and Dupont-Nivet, Guillaume and Bernet, Matthias and Mark, Chris and Wijbrans, Jan},
  title     = {Early onset and late acceleration of rapid exhumation in the Namche Barwa syntaxis, eastern Himalaya},
  series = {Geology},
  volume    = {48},
  journal   = {Geology},
  number    = {12},
  publisher = {American Institute of Physics},
  address   = {Boulder},
  issn      = {0091-7613},
  doi       = {10.1130/G47720.1},
  pages     = {1139 -- 1143},
  year      = {2020},
  abstract  = {The Himalayan syntaxes, characterized by extreme rates of rock exhumation co-located with major trans-orogenic rivers, figure prominently in the debate on tectonic versus erosional forcing of exhumation. Both the mechanism and timing of rapid exhumation of the Namche Barwa massif in the eastern syntaxis remain controversial. It has been argued that coupling between crustal rock advection and surface erosion initiated in the late Miocene (8-10 Ma). Recent studies, in contrast, suggest a Quaternary onset of rapid exhumation linked to a purely tectonic mechanism. We report new multisystem detrital thermochronology data from the most proximal Neogene clastic sediments downstream of Namche Barwa and use a thermo-kinematic model constrained by new and published data to explore its exhumation history. Modeling results show that exhumation accelerated to similar to 4 km/m.y. at ca. 8 Ma and to similar to 9 km/m.y. after ca. 2 Ma. This three-stage history reconciles apparently contradictory evidence for early and late onset of rapid exhumation and suggests efficient coupling between tectonics and erosion since the late Miocene. Quaternary acceleration of exhumation is consistent with river-profile evolution and may be linked to a Quaternary river-capture event.},
  language  = {en}
}