@article{DurandvandenBroekeLeCozannetetal.2022, author = {Durand, Gael and van den Broeke, Michiel R. and Le Cozannet, Goneri and Edwards, Tamsin L. and Holland, Paul R. and Jourdain, Nicolas C. and Marzeion, Ben and Mottram, Ruth and Nicholls, Robert J. and Pattyn, Frank and Paul, Frank and Slangen, Aimee B. A. and Winkelmann, Ricarda and Burgard, Clara and van Calcar, Caroline J. and Barre, Jean-Baptiste and Bataille, Amelie and Chapuis, Anne}, title = {Sea-Level rise: from global perspectives to local services}, series = {Frontiers in Marine Science}, volume = {8}, journal = {Frontiers in Marine Science}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {2296-7745}, doi = {10.3389/fmars.2021.709595}, pages = {8}, year = {2022}, abstract = {Coastal areas are highly diverse, ecologically rich, regions of key socio-economic activity, and are particularly sensitive to sea-level change. Over most of the 20th century, global mean sea level has risen mainly due to warming and subsequent expansion of the upper ocean layers as well as the melting of glaciers and ice caps. Over the last three decades, increased mass loss of the Greenland and Antarctic ice sheets has also started to contribute significantly to contemporary sea-level rise. The future mass loss of the two ice sheets, which combined represent a sea-level rise potential of similar to 65 m, constitutes the main source of uncertainty in long-term (centennial to millennial) sea-level rise projections. Improved knowledge of the magnitude and rate of future sea-level change is therefore of utmost importance. Moreover, sea level does not change uniformly across the globe and can differ greatly at both regional and local scales. The most appropriate and feasible sea level mitigation and adaptation measures in coastal regions strongly depend on local land use and associated risk aversion. Here, we advocate that addressing the problem of future sea-level rise and its impacts requires (i) bringing together a transdisciplinary scientific community, from climate and cryospheric scientists to coastal impact specialists, and (ii) interacting closely and iteratively with users and local stakeholders to co-design and co-build coastal climate services, including addressing the high-end risks.}, language = {en} } @article{KothariBattistiBooteetal.2022, author = {Kothari, Kritika and Battisti, Rafael and Boote, Kenneth J. and Archontoulis, Sotirios and Confalone, Adriana and Constantin, Julie and Cuadra, Santiago and Debaeke, Philippe and Faye, Babacar and Grant, Brian and Hoogenboom, Gerrit and Jing, Qi and van der Laan, Michael and Macena da Silva, Fernando Antonio and Marin, Fabio R. and Nehbandani, Alireza and Nendel, Claas and Purcell, Larry C. and Qian, Budong and Ruane, Alex C. and Schoving, Celine and Silva, Evandro H. F. M. and Smith, Ward and Soltani, Afshin and Srivastava, Amit and Vieira, Nilson A. and Slone, Stacey and Salmeron, Montserrat}, title = {Are soybean models ready for climate change food impact assessments?}, series = {European journal of agronomy : the official journal of the European Society for Agronomy}, volume = {135}, journal = {European journal of agronomy : the official journal of the European Society for Agronomy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1161-0301}, doi = {10.1016/j.eja.2022.126482}, pages = {15}, year = {2022}, abstract = {An accurate estimation of crop yield under climate change scenarios is essential to quantify our ability to feed a growing population and develop agronomic adaptations to meet future food demand. A coordinated evaluation of yield simulations from process-based eco-physiological models for climate change impact assessment is still missing for soybean, the most widely grown grain legume and the main source of protein in our food chain. In this first soybean multi-model study, we used ten prominent models capable of simulating soybean yield under varying temperature and atmospheric CO2 concentration [CO2] to quantify the uncertainty in soybean yield simulations in response to these factors. Models were first parametrized with high quality measured data from five contrasting environments. We found considerable variability among models in simulated yield responses to increasing temperature and [CO2]. For example, under a + 3 degrees C temperature rise in our coolest location in Argentina, some models simulated that yield would reduce as much as 24\%, while others simulated yield increases up to 29\%. In our warmest location in Brazil, the models simulated a yield reduction ranging from a 38\% decrease under + 3 degrees C temperature rise to no effect on yield. Similarly, when increasing [CO2] from 360 to 540 ppm, the models simulated a yield increase that ranged from 6\% to 31\%. Model calibration did not reduce variability across models but had an unexpected effect on modifying yield responses to temperature for some of the models. The high uncertainty in model responses indicates the limited applicability of individual models for climate change food projections. However, the ensemble mean of simulations across models was an effective tool to reduce the high uncertainty in soybean yield simulations associated with individual models and their parametrization. Ensemble mean yield responses to temperature and [CO2] were similar to those reported from the literature. Our study is the first demonstration of the benefits achieved from using an ensemble of grain legume models for climate change food projections, and highlights that further soybean model development with experiments under elevated [CO2] and temperature is needed to reduce the uncertainty from the individual models.}, language = {en} } @article{RajewarMohanaLakshmiMohantyetal.2021, author = {Rajewar, S. K. and Mohana Lakshmi, Ch. and Mohanty, Aditya and Pandey, Dwijendra N. and Pandey, Anshuman and Chaurasia, Anurag and Pandey, Ananya and Rajeswar Rao, V. and Naidu, M. S. and Kumar, Amit and Mondal, Saroj K. and Yadav, Rajeev K. and Catherine, J. K. and Giri, R. K. and Gahalaut, Vineet Kumar}, title = {Constraining plate motion and crustal deformation from GNSS measurements}, series = {Journal of the Geological Society of India}, volume = {97}, journal = {Journal of the Geological Society of India}, number = {10}, publisher = {Springer India}, address = {New Delhi}, issn = {0974-6889}, doi = {10.1007/s12594-021-1850-8}, pages = {1207 -- 1213}, year = {2021}, abstract = {Geodetic studies of crustal deformation using Global Navigation Satellite System (GNSS, earlier commonly referred to as Global Positioning System, GPS) measurements at CSIR-NGRI started in 1995 with the installation of a permanent GNSS station at CSIR-NGRI Hyderabad which later became an International GNSS Service (IGS) site. The CSIR-NGRI started expanding its GNSS networks after 2003 with more focussed studies through installation in the NE India, Himalayan arc, Andaman subduction zone, stable and failed rift regions of India plate. In each instance, these measurements helped in unravelling the geodynamics of the region and seismic hazard assessment, e.g., the discovery of a plate boundary fault in the Indo-Burmese wedge, rate and mode of strain accumulation and its spatial variation in the Garhwal-Kumaun and Kashmir region of the Himalayan arc, the influence of non-tectonic deformation on tectonic deformation in the Himalayan arc, nature of crustal deformation through earthquake cycle in the Andaman Sumatra subduction zone, and localised deformation in the intraplate region and across the paleo rift regions. Besides these, GNSS measurements initiated in the Antarctica region have helped in understanding the plate motion and influence of seasonal variations on deformation. Another important by-product of the GNSS observations is the capabilities of these observations in understanding the ionospheric variations due to earthquake processes and also due to solar eclipse. We summarize these outcomes in this article.}, language = {en} } @article{PłociennikZawiskaRzodkiewiczetal.2022, author = {Pł{\´o}ciennik, Mateusz and Zawiska, Izabela and Rzodkiewicz, Monika and Noryśkiewicz, Agnieszka M. and Słowiński, Michał and M{\"u}ller, Daniela and Brauer, Achim and Antczak-Orlewska, Olga and Kramkowski, Mateusz and Peyron, Odile and Nevalainen, Liisa and Luoto, Tomi P. and Kotrys, Bartosz and Sepp{\"a}, Heikki and Bidaurreta, Jon Camuera and Rudna, Marta and Mielczarek, Małgorzata and Zawisza, Edyta and Janowska, Ewa and Błaszkiewicz, Mirosław}, title = {Climatic and hydrological variability as a driver of the Lake Gościąż biota during the Younger Dryas}, series = {Catena}, volume = {212}, journal = {Catena}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0341-8162}, doi = {10.1016/j.catena.2022.106049}, pages = {15}, year = {2022}, abstract = {The Younger Dryas (YD) is a roughly 1,100-year cold period marking the end of the last glaciation. Climate modelling for northern Europe indicates high summer temperatures and strong continentality. In eastern Europe, the scale of temperature variation and its influence on ecosystems is weakly recognised. Here, we present a multi-proxy reconstruction of YD conditions from Lake Gos ' ciaz (central Poland). The decadal-resolution analysis of its annually varved sediments indicates an initial decrease in Chironomidae-inferred mean July air temperature followed by steady warming. The pollen-inferred winter-to-summer temperature amplitude and annual precip-itation is highest at the Allerod/YD transition and the early YD (ca. 12.7-12.4 ky cal BP) and YD/Holocene (11.7-11.4 ka cal BP) transition. Temperature and precipitation were the main reasons for lake level fluctuations as reflected in the planktonic/littoral Cladocera ratio. The lake's diatom-inferred total phosphorus decreased with increasing summer temperature from about mid YD. Windy conditions in the early YD until ~12.3 ka cal BP caused water mixing and a short-lived/temporary increase in nutrient availability for phytoplankton. The Chironomidae-inferred summer temperature and pollen inferred summer temperature, winter temperature and annual precipitation herein are one of only a few in eastern Europe conducted with such high resolution.}, language = {en} } @article{LupienRussellPearsonetal.2022, author = {Lupien, Rachel L. and Russell, James M. and Pearson, Emma J. and Castaneda, Isla S. and Asrat, Asfawossen and F{\"o}rster, Verena and Lamb, Henry F. and Roberts, Helen M. and Sch{\"a}bitz, Frank and Trauth, Martin H. and Beck, Catherine C. and Feibel, Craig S. and Cohen, Andrew S.}, title = {Orbital controls on eastern African hydroclimate in the Pleistocene}, series = {Scientific reports}, volume = {12}, journal = {Scientific reports}, number = {1}, publisher = {Macmillan Publishers Limited}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-022-06826-z}, pages = {10}, year = {2022}, abstract = {Understanding eastern African paleoclimate is critical for contextualizing early human evolution, adaptation, and dispersal, yet Pleistocene climate of this region and its governing mechanisms remain poorly understood due to the lack of long, orbitally-resolved, terrestrial paleoclimate records. Here we present leaf wax hydrogen isotope records of rainfall from paleolake sediment cores from key time windows that resolve long-term trends, variations, and high-latitude effects on tropical African precipitation. Eastern African rainfall was dominantly controlled by variations in low-latitude summer insolation during most of the early and middle Pleistocene, with little evidence that glacial-interglacial cycles impacted rainfall until the late Pleistocene. We observe the influence of high-latitude-driven climate processes emerging from the last interglacial (Marine Isotope Stage 5) to the present, an interval when glacial-interglacial cycles were strong and insolation forcing was weak. Our results demonstrate a variable response of eastern African rainfall to low-latitude insolation forcing and high-latitude-driven climate change, likely related to the relative strengths of these forcings through time and a threshold in monsoon sensitivity. We observe little difference in mean rainfall between the early, middle, and late Pleistocene, which suggests that orbitally-driven climate variations likely played a more significant role than gradual change in the relationship between early humans and their environment.}, language = {en} } @article{DeFelipeAlcaldeBaykievetal.2022, author = {DeFelipe, Irene and Alcalde, Juan and Baykiev, Eldar and Bernal, Isabel and Boonma, Kittiphon and Carbonell, Ramon and Flude, Stephanie and Folch, Arnau and Fullea, Javier and Garc{\´i}a-Castellanos, Daniel and Geyer, Adelina and Giralt, Santiago and Hern{\´a}ndez, Armand and Jim{\´e}nez-Munt, Ivone and Kumar, Ajay and Llorens, Maria-Gema and Mart{\´i}, Joan and Molina, Cecilia and Olivar-Casta{\~n}o, Andr{\´e}s and Parnell, Andrew and Schimmel, Martin and Torn{\´e}, Montserrat and Ventosa, Sergi}, title = {Towards a digital twin of the Earth system: Geo-Soft-CoRe, a geoscientific software \& code repository}, series = {Frontiers in earth science}, volume = {10}, journal = {Frontiers in earth science}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {2296-6463}, doi = {10.3389/feart.2022.828005}, pages = {20}, year = {2022}, abstract = {The immense advances in computer power achieved in the last decades have had a significant impact in Earth science, providing valuable research outputs that allow the simulation of complex natural processes and systems, and generating improved forecasts. The development and implementation of innovative geoscientific software is currently evolving towards a sustainable and efficient development by integrating models of different aspects of the Earth system. This will set the foundation for a future digital twin of the Earth. The codification and update of this software require great effort from research groups and therefore, it needs to be preserved for its reuse by future generations of geoscientists. Here, we report on Geo-Soft-CoRe, a Geoscientific Software \& Code Repository, hosted at the archive DIGITAL.CSIC. This is an open source, multidisciplinary and multiscale collection of software and code developed to analyze different aspects of the Earth system, encompassing tools to: 1) analyze climate variability; 2) assess hazards, and 3) characterize the structure and dynamics of the solid Earth. Due to the broad range of applications of these software packages, this collection is useful not only for basic research in Earth science, but also for applied research and educational purposes, reducing the gap between the geosciences and the society. By providing each software and code with a permanent identifier (DOI), we ensure its self-sustainability and accomplish the FAIR (Findable, Accessible, Interoperable and Reusable) principles. Therefore, we aim for a more transparent science, transferring knowledge in an easier way to the geoscience community, and encouraging an integrated use of computational infrastructure.}, language = {en} } @article{RosaDewaeleGarbarinoetal.2022, author = {Rosa, Angelika D. and Dewaele, Agn{\`e}s and Garbarino, Gaston and Svitlyk, Volodymyr and Morard, Guillaume and De Angelis, Filippo and Krstulovic, Marija and Briggs, Richard and Irifune, Tetsuo and Mathon, Olivier and Bouhifd, Mohamed Ali}, title = {Martensitic fcc-hcp transformation pathway in solid krypton and xenon and its effect on their equations of state}, series = {Physical review / publ. by The American Institute of Physics. B}, volume = {105}, journal = {Physical review / publ. by The American Institute of Physics. B}, number = {14}, publisher = {American Physical Society}, address = {College Park}, issn = {2469-9950}, doi = {10.1103/PhysRevB.105.144103}, pages = {14}, year = {2022}, abstract = {The martensitic transformation is a fundamental physical phenomenon at the origin of important industrial applications. However, the underlying microscopic mechanism, which is of critical importance to explain the outstanding mechanical properties of martensitic materials, is still not fully understood. This is because for most martensitic materials the transformation is a fast process that makes in situ studies extremely challenging. Noble solids krypton and xenon undergo a progressive pressure-induced face-centered cubic (fcc) to hexagonal close-packed (hcp) martensitic transition with a very wide coexistence domain. Here, we took advantage of this unique feature to study the detailed transformation progress at the atomic level by employing in situ x-ray diffraction and absorption spectroscopy. We evidenced a four-stage pathway and suggest that the lattice mismatch between the fcc and hcp forms plays a key role in the generation of strain. We also determined precisely the effect of the transformation on the compression behavior of these materials.}, language = {en} } @article{KutzschbachWunderWannhoffetal.2021, author = {Kutzschbach, Martin and Wunder, Bernd and Wannhoff, Iris and Wilke, Franziska Daniela Helena and Couffignal, Fr{\´e}d{\´e}ric and Rocholl, Alexander}, title = {Raman spectroscopic quantification of tetrahedral boron in synthetic aluminum-rich tourmaline}, series = {American mineralogist : an international journal of earth and planetary materials}, volume = {106}, journal = {American mineralogist : an international journal of earth and planetary materials}, number = {6}, publisher = {Mineralogical Society of America}, address = {Washington, DC [u.a.]}, issn = {0003-004X}, doi = {10.2138/am-2021-7758}, pages = {872 -- 882}, year = {2021}, abstract = {The Raman spectra of five B-[4]-bearing tourmalines of different composition synthesized at 700 degrees C/4.0 GPa (including first-time synthesis of Na-Li-B-[4]-tourmaline, Ca-Li-B-[4]-tourmaline, and Ca-bearing square-B-[4]-tourmaline) reveal a strong correlation between the tetrahedral boron content and the summed relative intensity of all OH-stretching bands between 3300-3430 cm(-1). The band shift to low wavenumbers is explained by strong O3-H center dot center dot center dot O5 hydrogen bridge bonding. Applying the regression equation to natural B-[4]-bearing tourmaline from the Koralpe (Austria) reproduces the EMPA-derived value perfectly [EMPA: 0.67(12) B-[4] pfu vs. Raman: 0.66(13) B-[4] pfu]. This demonstrates that Raman spectroscopy provides a fast and easy-to-use tool for the quantification of tetrahedral boron in tourmaline. The knowledge of the amount of tetrahedral boron in tourmaline has important implications for the better understanding and modeling of B-isotope fractionation between tourmaline and fluid/melt, widely used as a tracer of mass transfer processes.}, language = {en} } @article{FarkasHofmannZimmermannetal.2021, author = {Farkas, M{\´a}rton P{\´a}l and Hofmann, Hannes and Zimmermann, G{\"u}nter and Zang, Arno and Bethmann, Falko and Meier, Peter and Cottrell, Mark and Josephson, Neal}, title = {Hydromechanical analysis of the second hydraulic stimulation in well PX-1 at the Pohang fractured geothermal reservoir, South Korea}, series = {Geothermics : an international journal of geothermal research and its applications}, volume = {89}, journal = {Geothermics : an international journal of geothermal research and its applications}, publisher = {Elsevier}, address = {Amsterdam [u.a.]}, issn = {0375-6505}, doi = {10.1016/j.geothermics.2020.101990}, pages = {13}, year = {2021}, abstract = {In this study, we investigate numerically the hydro-mechanical behavior of fractured crystalline rock due to one of the five hydraulic stimulations at the Pohang Enhanced Geothermal site in South Korea. We use the commercial code FracMan (Golder Associates) that enables studying hydro-mechanical coupled processes in fractured media in three dimensions combining the finite element method with a discrete fracture network. The software is used to simulate fluid pressure perturbation at fractures during hydraulic stimulation. Our numerical simulation shows that pressure history matching can be obtained by partitioning the treatment into separate phases. This results in adjusted stress-aperture relationships. The evolution of aperture adjustment implies that the stimulation mechanism could be a combination of hydraulic fracturing and shearing. The simulated extent of the 0.01 MPa overpressure contour at the end of the treatment equals to similar to 180 m around the injection point.}, language = {en} } @article{LichtKelsonBergeletal.2022, author = {Licht, Alexis and Kelson, Julia and Bergel, Shelly J. and Schauer, Andrew J. and Petersen, Sierra Victoria and Capirala, Ashika and Huntington, Katharine W. and Dupont-Nivet, Guillaume and Win, Zaw and Aung, Day Wa}, title = {Dynamics of pedogenic carbonate growth in the tropical domain of Myanmar}, series = {Geochemistry, geophysics, geosystems}, volume = {23}, journal = {Geochemistry, geophysics, geosystems}, number = {7}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1029/2021GC009929}, pages = {15}, year = {2022}, abstract = {Pedogenic carbonate is widespread at mid latitudes where warm and dry conditions favor soil carbonate growth from spring to fall. The mechanisms and timing of pedogenic carbonate formation are more ambiguous in the tropical domain, where long periods of soil water saturation and high soil respiration enhance calcite dissolution. This paper provides stable carbon, oxygen and clumped isotope values from Quaternary and Miocene pedogenic carbonates in the tropical domain of Myanmar, in areas characterized by warm (>18°C) winters and annual rainfall up to 1,700 mm. We show that carbonate growth in Myanmar is delayed to the driest and coldest months of the year by sustained monsoonal rainfall from mid spring to late fall. The range of isotopic variability in Quaternary pedogenic carbonates can be solely explained by temporal changes of carbonate growth within the dry season, from winter to early spring. We propose that high soil moisture year-round in the tropical domain narrows carbonate growth to the driest months and makes it particularly sensitive to the seasonal distribution of rainfall. This sensitivity is also enabled by high winter temperatures, allowing carbonate growth to occur outside the warmest months of the year. This high sensitivity is expected to be more prominent in the geological record during times with higher temperatures and greater expansion of the tropical realm. Clumped isotope temperatures, δ13C and δ18O values of tropical pedogenic carbonates are impacted by changes of both rainfall seasonality and surface temperatures; this sensitivity can potentially be used to track past tropical rainfall distribution.}, language = {en} } @article{SharmaHainzlZoeller2023, author = {Sharma, Shubham and Hainzl, Sebastian and Z{\"o}ller, Gert}, title = {Seismicity parameters dependence on main shock-induced co-seismic stress}, series = {Geophysical journal international}, volume = {235}, journal = {Geophysical journal international}, number = {1}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0956-540X}, doi = {10.1093/gji/ggad201}, pages = {509 -- 517}, year = {2023}, abstract = {The Gutenberg-Richter (GR) and the Omori-Utsu (OU) law describe the earthquakes' energy release and temporal clustering and are thus of great importance for seismic hazard assessment. Motivated by experimental results, which indicate stress-dependent parameters, we consider a combined global data set of 127 main shock-aftershock sequences and perform a systematic study of the relationship between main shock-induced stress changes and associated seismicity patterns. For this purpose, we calculate space-dependent Coulomb Stress (\& UDelta;CFS) and alternative receiver-independent stress metrics in the surrounding of the main shocks. Our results indicate a clear positive correlation between the GR b-value and the induced stress, contrasting expectations from laboratory experiments and suggesting a crucial role of structural heterogeneity and strength variations. Furthermore, we demonstrate that the aftershock productivity increases nonlinearly with stress, while the OU parameters c and p systematically decrease for increasing stress changes. Our partly unexpected findings can have an important impact on future estimations of the aftershock hazard.}, language = {en} } @article{DuttaJonssonVasyuraBathke2021, author = {Dutta, Rishabh and J{\´o}nsson, Sigurj{\´o}n and Vasyura-Bathke, Hannes}, title = {Simultaneous Bayesian estimation of non-planar fault geometry and spatially-variable slip}, series = {JGR / AGU, American Geophysical Union : Solid earth}, volume = {126}, journal = {JGR / AGU, American Geophysical Union : Solid earth}, number = {7}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {2169-9313}, doi = {10.1029/2020JB020441}, pages = {28}, year = {2021}, abstract = {Large earthquakes are usually modeled with simple planar fault surfaces or a combination of several planar fault segments. However, in general, earthquakes occur on faults that are non-planar and exhibit significant geometrical variations in both the along-strike and down-dip directions at all spatial scales. Mapping of surface fault ruptures and high-resolution geodetic observations are increasingly revealing complex fault geometries near the surface and accurate locations of aftershocks often indicate geometrical complexities at depth. With better geodetic data and observations of fault ruptures, more details of complex fault geometries can be estimated resulting in more realistic fault models of large earthquakes. To address this topic, we here parametrize non-planar fault geometries with a set of polynomial parameters that allow for both along-strike and down-dip variations in the fault geometry. Our methodology uses Bayesian inference to estimate the non-planar fault parameters from geodetic data, yielding an ensemble of plausible models that characterize the uncertainties of the non-planar fault geometry and the fault slip. The method is demonstrated using synthetic tests considering slip spatially distributed on a single continuous finite non-planar fault surface with varying dip and strike angles both in the down-dip and along-strike directions. The results show that fault-slip estimations can be biased when a simple planar fault geometry is assumed in presence of significant non-planar geometrical variations. Our method can help to model earthquake fault sources in a more realistic way and may be extended to include multiple non-planar fault segments or other geometrical fault complexities.}, language = {en} } @article{BlankeKwiatekGoebeletal.2021, author = {Blanke, Aglaja and Kwiatek, Grzegorz and Goebel, Thomas H. W. and Bohnhoff, Marco and Dresen, Georg}, title = {Stress drop-magnitude dependence of acoustic emissions during laboratory stick-slip}, series = {Geophysical journal international / the Royal Astronomical Society, the Deutsche Geophysikalische Gesellschaft and the European Geophysical Society}, volume = {224}, journal = {Geophysical journal international / the Royal Astronomical Society, the Deutsche Geophysikalische Gesellschaft and the European Geophysical Society}, number = {2}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0956-540X}, doi = {10.1093/gji/ggaa524}, pages = {1372 -- 1381}, year = {2021}, abstract = {Earthquake source parameters such as seismic stress drop and corner frequency are observed to vary widely, leading to persistent discussion on potential scaling of stress drop and event size. Physical mechanisms that govern stress drop variations arc difficult to evaluate in nature and are more readily studied in controlled laboratory experiments. We perform two stick-slip experiments on fractured (rough) and cut (smooth) Westerly granite samples to explore fault roughness effects on acoustic emission (AE) source parameters. We separate large stick-slip events that generally saturate the seismic recording system from populations of smaller AE events which are sensitive to fault stresses prior to slip. AE event populations show many similarities to natural seismicity and may be interpreted as laboratory equivalent of natural microseismic events. We then compare the temporal evolution of mechanical data such as measured stress release during slip to temporal changes in stress drops derived from Alis using the spectral ratio technique. We report on two primary observations: (1) In contrast to most case studies for natural earthquakes, we observe a strong increase in seismic stress drop with AE size. (2) The scaling of stress drop with magnitude is governed by fault roughness, whereby the rough fault shows a more rapid increase of the stress drop magnitude relation with progressing large stick-slip events than the smooth fault. The overall range of AE sizes on the rough surface is influenced by both the average grain size and the width of the fault core. The magnitudes of the smallest AE events on smooth faults may also be governed by grain size. However, AEs significantly grow beyond peak roughness and the width of the fault core. Our laboratory tests highlight that source parameters vary substantially in the presence of fault zone heterogeneity (i.e. roughness and narrow grain size distribution), which may affect seismic energy partitioning and static stress drops of small and large AE events.}, language = {en} } @article{NajmanSobelMillaretal.2022, author = {Najman, Yani and Sobel, Edward and Millar, Ian and Luan, Xiwu and Zapata, Sebastian and Garzanti, Eduardo and Parra, Mauricio and Vezzoli, Giovanni and Zhang, Peng and Wa Aung, Day and Paw, Saw Mu Tha Lay and Lwin, Thae Naung}, title = {The timing of collision between Asia and the West Burma Terrane, and the development of the Indo-Burman Ranges}, series = {Tectonics}, volume = {41}, journal = {Tectonics}, number = {7}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0278-7407}, doi = {10.1029/2021TC007057}, pages = {22}, year = {2022}, abstract = {The West Burma Terrane (WBT) is a small terrane bounded to the east by the Asian Sibumasu Block and to the west by the Indo-Burman Ranges (IBR), the latter being an exhumed accretionary prism that formed during subduction of Indian oceanic lithosphere beneath Asia. Understanding the geological history of the WBT is important for reconstruction of the closure history of the Tethys Ocean and India-Asia collision. Currently there are major discrepancies in the proposed timings of collision between the WBT with both India and Asia; whether the WBT collided with India or Asia first is debated, and proposed timings of collisions stretch from the Mesozoic to the Cenozoic. We undertook a multi-technique provenance study involving petrography, detrital zircon U-Pb and Hf analyses, rutile U-Pb analyses and Sr-Nd bulk rock analyses on sediments of the Central Myanmar Basins of the WBT. We determined that the first arrival of Asian material into the basin occurred after the earliest late Eocene and by the early Oligocene, thus placing a minimum constraint on the timing of WBT-Asia collision. Our low temperature thermochronological study of the IBR records two periods of exhumation, in the early-middle Eocene, and at the Oligo-Miocene boundary. The Eocene event may be associated with the collision of the WBT with India. The later event at the Oligo-Miocene boundary may be associated with changes in wedge dynamics resulting from increased sediment supply to the system; however a number of other possible causes provide equally plausible explanations for both events.}, language = {en} } @article{ToumoulinTardifBecquetDonnadieuetal.2022, author = {Toumoulin, Agathe and Tardif-Becquet, Delphine and Donnadieu, Yannick and Licht, Alexis and Ladant, Jean-Baptiste and Kunzmann, Lutz and Dupont-Nivet, Guillaume}, title = {Evolution of continental temperature seasonality from the Eocene greenhouse to the Oligocene icehouse}, series = {Climate of the past : an interactive open access journal of the European Geosciences Union}, volume = {18}, journal = {Climate of the past : an interactive open access journal of the European Geosciences Union}, number = {2}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1814-9324}, doi = {10.5194/cp-18-341-2022}, pages = {341 -- 362}, year = {2022}, abstract = {At the junction of greenhouse and icehouse climate states, the Eocene-Oligocene Transition (EOT) is a key moment in Cenozoic climate history. While it is associated with severe extinctions and biodiversity turnovers on land, the role of terrestrial climate evolution remains poorly resolved, especially the associated changes in seasonality. Some paleobotanical and geochemical continental records in parts of the Northern Hemisphere suggest the EOT is associated with a marked cooling in winter, leading to the development of more pronounced seasons (i.e., an increase in the mean annual range of temperature, MATR). However, the MATR increase has been barely studied by climate models and large uncertainties remain on its origin, geographical extent and impact. In order to better understand and describe temperature seasonality changes between the middle Eocene and the early Oligocene, we use the Earth system model IPSL-CM5A2 and a set of simulations reconstructing the EOT through three major climate forcings: pCO(2) decrease (1120, 840 and 560 ppm), the Antarctic ice-sheet (AIS) formation and the associated sea-level decrease. Our simulations suggest that pCO(2) lowering alone is not sufficient to explain the seasonality evolution described by the data through the EOT but rather that the combined effects of pCO(2) , AIS formation and increased continentality provide the best data-model agreement.pCO(2) decrease induces a zonal pattern with alternating increasing and decreasing seasonality bands particularly strong in the northern high latitudes (up to 8 degrees C MATR increase) due to sea-ice and surface albedo feedback. Conversely, the onset of the AIS is responsible for a more constant surface albedo yearly, which leads to a strong decrease in seasonality in the southern midlatitudes to high latitudes (> 40 degrees S). Finally, continental areas that emerged due to the sea-level lowering cause the largest increase in seasonality and explain most of the global heterogeneity in MATR changes (1MATR) patterns. The Delta MATR patterns we reconstruct are generally consistent with the variability of the EOT biotic crisis intensity across the Northern Hemisphere and provide insights on their underlying mechanisms.}, language = {en} } @article{SmithBoers2023, author = {Smith, Taylor and Boers, Niklas}, title = {Global vegetation resilience linked to water availability and variability}, series = {Nature Communications}, volume = {14}, journal = {Nature Communications}, number = {1}, publisher = {Springer Nature}, address = {London}, issn = {2041-1723}, doi = {10.1038/s41467-023-36207-7}, pages = {11}, year = {2023}, abstract = {Quantifying the resilience of vegetated ecosystems is key to constraining both present-day and future global impacts of anthropogenic climate change. Here we apply both empirical and theoretical resilience metrics to remotely-sensed vegetation data in order to examine the role of water availability and variability in controlling vegetation resilience at the global scale. We find a concise global relationship where vegetation resilience is greater in regions with higher water availability. We also reveal that resilience is lower in regions with more pronounced inter-annual precipitation variability, but find less concise relationships between vegetation resilience and intra-annual precipitation variability. Our results thus imply that the resilience of vegetation responds differently to water deficits at varying time scales. In view of projected increases in precipitation variability, our findings highlight the risk of ecosystem degradation under ongoing climate change. Vegetation dynamics depend on both the amount of precipitation and its variability over time. Here, the authors show that vegetation resilience is greater where water availability is higher and where precipitation is more stable from year to year.}, language = {en} } @article{RepaschScheingrossHoviusetal.2022, author = {Repasch, Marisa and Scheingross, Joel S. and Hovius, Niels and Vieth-Hillebrand, Andrea and Mueller, Carsten W. and H{\"o}schen, Carmen and Szupiany, Ricardo N. and Sachse, Dirk}, title = {River organic carbon fluxes modulated by hydrodynamic sorting of particulate organic matter}, series = {Geophysical research letters}, volume = {49}, journal = {Geophysical research letters}, number = {3}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0094-8276}, doi = {10.1029/2021GL096343}, pages = {11}, year = {2022}, abstract = {Rivers regulate the global carbon cycle by transferring particulate organic carbon (POC) from terrestrial landscapes to marine sedimentary basins, but the processes controlling the amount and composition of fluvially exported POC are poorly understood. We propose that hydrodynamic sorting processes modify POC fluxes during fluvial transit. We test this hypothesis by studying POC transported along a similar to 1,200 km reach of the Rio Bermejo, Argentina. Nanoscale secondary ion mass spectrometry revealed that POC was either fine, mineral-associated organic matter, or coarse discrete organic particles. Mineral-associated POC is more resistant to oxidation and has a lower particle settling velocity than discrete POC. Consequently, hydraulic sorting and downstream fining amplify the proportion of fine, mineral-associated POC from similar to 55\% to similar to 78\% over 1,220 km of downstream transit. This suggests that mineral-associated POC has a greater probability of export and preservation in marine basins than plant detritus, which may be oxidized to CO2 during transit.}, language = {en} } @article{VoglimacciStephanopoliWendlederLantuitetal.2022, author = {Voglimacci-Stephanopoli, Jo{\"e}lle and Wendleder, Anna and Lantuit, Hugues and Langlois, Alexandre and Stettner, Samuel and Schmitt, Andreas and Dedieu, Jean-Pierre and Roth, Achim and Royer, Alain}, title = {Potential of X-band polarimetric synthetic aperture radar co-polar phase difference for arctic snow depth estimation}, series = {Cryosphere}, volume = {16}, journal = {Cryosphere}, number = {6}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1994-0416}, doi = {10.5194/tc-16-2163-2022}, pages = {2163 -- 2181}, year = {2022}, abstract = {Changes in snowpack associated with climatic warming has drastic impacts on surface energy balance in the cryosphere. Yet, traditional monitoring techniques, such as punctual measurements in the field, do not cover the full snowpack spatial and temporal variability, which hampers efforts to upscale measurements to the global scale. This variability is one of the primary constraints in model development. In terms of spatial resolution, active microwaves (synthetic aperture radar - SAR) can address the issue and outperform methods based on passive microwaves. Thus, high-spatial-resolution monitoring of snow depth (SD) would allow for better parameterization of local processes that drive the spatial variability of snow. The overall objective of this study is to evaluate the potential of the TerraSAR-X (TSX) SAR sensor and the wave co-polar phase difference (CPD) method for characterizing snow cover at high spatial resolution. Consequently, we first (1) investigate SD and depth hoar fraction (DHF) variability between different vegetation classes in the Ice Creek catchment (Qikiqtaruk/Herschel Island, Yukon, Canada) using in situ measurements collected over the course of a field campaign in 2019; (2) evaluate linkages between snow characteristics and CPD distribution over the 2019 dataset; and (3) determine CPD seasonality considering meteorological data over the 2015-2019 period. SD could be extracted using the CPD when certain conditions are met. A high incidence angle (>30 circle) with a high topographic wetness index (TWI) (>7.0) showed correlation between SD and CPD (R2 up to 0.72). Further, future work should address a threshold of sensitivity to TWI and incidence angle to map snow depth in such environments and assess the potential of using interpolation tools to fill in gaps in SD information on drier vegetation types.}, language = {en} } @article{HaugkJongejansMangelsdorfetal.2022, author = {Haugk, Charlotte and Jongejans, Loeka L. and Mangelsdorf, Kai and Fuchs, Matthias and Ogneva, Olga and Palmtag, Juri and Mollenhauer, Gesine and Mann, Paul J. and Overduin, P. Paul and Grosse, Guido and Sanders, Tina and Tuerena, Robyn E. and Schirrmeister, Lutz and Wetterich, Sebastian and Kizyakov, Alexander and Karger, Cornelia and Strauss, Jens}, title = {Organic matter characteristics of a rapidly eroding permafrost cliff in NE Siberia (Lena Delta, Laptev Sea region)}, series = {Biogeosciences}, volume = {19}, journal = {Biogeosciences}, number = {7}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-19-2079-2022}, pages = {2079 -- 2094}, year = {2022}, abstract = {Organic carbon (OC) stored in Arctic permafrost represents one of Earth's largest and most vulnerable terrestrial carbon pools. Amplified climate warming across the Arctic results in widespread permafrost thaw. Permafrost deposits exposed at river cliffs and coasts are particularly susceptible to thawing processes. Accelerating erosion of terrestrial permafrost along shorelines leads to increased transfer of organic matter (OM) to nearshore waters. However, the amount of terrestrial permafrost carbon and nitrogen as well as the OM quality in these deposits is still poorly quantified. We define the OM quality as the intrinsic potential for further transformation, decomposition and mineralisation. Here, we characterise the sources and the quality of OM supplied to the Lena River at a rapidly eroding permafrost river shoreline cliff in the eastern part of the delta (Sobo-Sise Island). Our multi-proxy approach captures bulk elemental, molecu- lar geochemical and carbon isotopic analyses of Late Pleistocene Yedoma permafrost and Holocene cover deposits, discontinuously spanning the last similar to 52 kyr. We showed that the ancient permafrost exposed in the Sobo-Sise cliff has a high organic carbon content (mean of about 5 wt \%). The oldest sediments stem from Marine Isotope Stage (MIS) 3 interstadial deposits (dated to 52 to 28 cal ka BP) and are overlaid by last glacial MIS 2 (dated to 28 to 15 cal ka BP) and Holocene MIS 1 (dated to 7-0 cal ka BP) deposits. The relatively high average chain length (ACL) index of n-alkanes along the cliff profile indicates a predominant contribution of vascular plants to the OM composition. The elevated ratio of isoand anteiso-branched fatty acids (FAs) relative to mid- and long-chain (C >= 20) n-FAs in the interstadial MIS 3 and the interglacial MIS 1 deposits suggests stronger microbial activity and consequently higher input of bacterial biomass during these climatically warmer periods. The overall high carbon preference index (CPI) and higher plant fatty acid (HPFA) values as well as high C/N ratios point to a good quality of the preserved OM and thus to a high potential of the OM for decomposition upon thaw. A decrease in HPFA values downwards along the profile probably indicates stronger OM decomposition in the oldest (MIS 3) deposits of the cliff. The characterisation of OM from eroding permafrost leads to a better assessment of the greenhouse gas potential of the OC released into river and nearshore waters in the future.}, language = {en} } @article{JaraMunozMelnickLietal.2022, author = {Jara-Mu{\~n}oz, Julius and Melnick, Daniel and Li, Shaoyang and Socquet, Anne and Cort{\´e}s-Aranda, Joaqu{\´i}n and Brill, Dominik and Strecker, Manfred R.}, title = {The cryptic seismic potential of the Pichilemu blind fault in Chile revealed by off-fault geomorphology}, series = {Nature communications}, volume = {13}, journal = {Nature communications}, number = {1}, publisher = {Nature Research}, address = {Berlin}, issn = {2041-1723}, doi = {10.1038/s41467-022-30754-1}, pages = {13}, year = {2022}, abstract = {The first step towards assessing hazards in seismically active regions involves mapping capable faults and estimating their recurrence times. While the mapping of active faults is commonly based on distinct geologic and geomorphic features evident at the surface, mapping blind seismogenic faults is complicated by the absence of on-fault diagnostic features. Here we investigated the Pichilemu Fault in coastal Chile, unknown until it generated a Mw 7.0 earthquake in 2010. The lack of evident surface faulting suggests activity along a partly-hidden blind fault. We used off-fault deformed marine terraces to estimate a fault-slip rate of 0.52 +/- 0.04 m/ka, which, when integrated with satellite geodesy suggests a 2.12 +/- 0.2 ka recurrence time for Mw similar to 7.0 normal-faulting earthquakes. We propose that extension in the Pichilemu region is associated with stress changes during megathrust earthquakes and accommodated by sporadic slip during upper-plate earthquakes, which has implications for assessing the seismic potential of cryptic faults along convergent margins and elsewhere.}, language = {en} }