TY - JOUR A1 - Timmerman, Martin Jan A1 - Krmicek, Lukas A1 - Krmíčková, Simona A1 - Slama, Jiri A1 - Sudo, Masafumi A1 - Sobel, Edward T1 - Tonian-Ediacaran evolution of the Brunovistulian microcontinent (Czech Republic) deciphered from LA-ICP-MS U-Pb zircon and 40Ar/39Ar muscovite ages JF - Precambrian research N2 - Granitoids of the Slavkov Domain of the Brunovistulian microcontinent (BVM) in the Czech Republic have Ediacaran U-Pb zircon crystallization ages with the dominant magmatic activity occurring between ca. 597 and 595 Ma. The ages overlap published ages for the adjacent Thaya Domain, showing that both domains formed coevally in the same subduction setting. The data support published models in which the Slavkov Domain formed as arc crust. The main stage of magmatism stopped after ca. 595-590 Ma and was quickly followed by cooling accompanied by intrusion of small volumes of rhyolite dykes at ca. 594 Ma. Slavkov Domain metasedimentary rocks are dominated by Cryogenian-Ediacaran detrital zircon populations and their protoliths were locally derived erosional products of Cryogenian to Ediacaran arc rocks of the Thaya and Slavkov domains. Metasedi-mentary rocks from the NE part of the BVM contain younger, ca. 550 Ma zircons indicating that the BVM grew northeastward by accretion of progressively younger material derived from magmatic rocks with latest Ediacaran crystallization ages. In contrast to the Thaya and Slavkov domains, the Metavolcanic Zone that lies between them formed between ca. 740 and 725 Ma in the late Tonian to early Cryogenian. It predates the main stage magmatic activity in the BVM by 135 to 150 Ma and is probably a relic of older crust that formed during rifting of the Rodinia supercontinent. At ca. 552-551 Ma in the latest Ediacaran, parts of the BVM were exposed at the surface, during which time red, terrestrial siliciclastic sediments (Basal Clastics) were deposited. These largely had (very) proximal sources such as the main stage granitoids of the Thaya and Slavkov domains. Clasts of (meta)sandstones contain much older zircon populations and provide evidence that Neoarchaean and Palaeo-, meso- and early Neoproterozoic crustal rocks were exposed in erosional position nearby. KW - Brunovistulicum KW - Cryogenian KW - Ediacaran KW - Basal Clastics KW - U -Pb dating KW - Ar KW - Ar dating Y1 - 2023 U6 - https://doi.org/10.1016/j.precamres.2023.106981 SN - 0301-9268 SN - 1872-7433 VL - 387 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Pfalz, Gregor T1 - Advancing knowledge of Arctic lake system dynamics: A data-driven perspective on spatiotemporal patterns T1 - Fortschritte im Verständnis der Dynamik arktischer Seesysteme: Eine datengetriebene Perspektive auf raumzeitliche Muster N2 - Ecosystems play a pivotal role in addressing climate change but are also highly susceptible to drastic environmental changes. Investigating their historical dynamics can enhance our understanding of how they might respond to unprecedented future environmental shifts. With Arctic lakes currently under substantial pressure from climate change, lessons from the past can guide our understanding of potential disruptions to these lakes. However, individual lake systems are multifaceted and complex. Traditional isolated lake studies often fail to provide a global perspective because localized nuances—like individual lake parameters, catchment areas, and lake histories—can overshadow broader conclusions. In light of these complexities, a more nuanced approach is essential to analyze lake systems in a global context. A key to addressing this challenge lies in the data-driven analysis of sedimentological records from various northern lake systems. This dissertation emphasizes lake systems in the northern Eurasian region, particularly in Russia (n=59). For this doctoral thesis, we collected sedimentological data from various sources, which required a standardized framework for further analysis. Therefore, we designed a conceptual model for integrating and standardizing heterogeneous multi-proxy data into a relational database management system (PostgreSQL). Creating a database from the collected data enabled comparative numerical analyses between spatially separated lakes as well as between different proxies. When analyzing numerous lakes, establishing a common frame of reference was crucial. We achieved this by converting proxy values from depth dependency to age dependency. This required consistent age calculations across all lakes and proxies using one age-depth modeling software. Recognizing the broader implications and potential pitfalls of this, we developed the LANDO approach ("Linked Age and Depth Modelling"). LANDO is an innovative integration of multiple age-depth modeling software into a singular, cohesive platform (Jupyter Notebook). Beyond its ability to aggregate data from five renowned age-depth modeling software, LANDO uniquely empowers users to filter out implausible model outcomes using robust geoscientific data. Our method is not only novel but also significantly enhances the accuracy and reliability of lake analyses. Considering the preceding steps, this doctoral thesis further examines the relationship between carbon in sediments and temperature over the last 21,000 years. Initially, we hypothesized a positive correlation between carbon accumulation in lakes and modelled paleotemperature. Our homogenized dataset from heterogeneous lakes confirmed this association, even if the highest temperatures throughout our observation period do not correlate with the highest carbon values. We assume that rapid warming events contribute more to high accumulation, while sustained warming leads to carbon outgassing. Considering the current high concentration of carbon in the atmosphere and rising temperatures, ongoing climate change could cause northern lake systems to contribute to a further increase in atmospheric carbon (positive feedback loop). While our findings underscore the reliability of both our standardized data and the LANDO method, expanding our dataset might offer even greater assurance in our conclusions. N2 - Ökosysteme spielen eine zentrale Rolle bei der Bewältigung des Klimawandels, gelten jedoch auch als äußerst anfällig für drastische Umweltveränderungen. Die Erforschung ihrer historischen Dynamiken kann unser Verständnis darüber verbessern, wie sich zukünftige Veränderungen angesichts beispielloser Umweltveränderungen auf sie auswirken können. Angesichts des enormen Stresses, dem arktische Seen durch den Klimawandel ausgesetzt sind, können konkrete Fälle aus der Vergangenheit helfen, mögliche Schwankungen im Ökosystem des Sees besser zu verstehen und zu deuten. Einzelne Seesysteme unterliegen jedoch einer inhärenten Komplexität und vielschichtigen Beschaffenheit. Klassische Einzelanalysen von Seen liefern oft keine globale Perspektive, da lokale Besonderheiten – wie individuelle Seeparameter, Einzugsgebiete und Seehistorien – allgemeinere Schlussfolgerungen überlagern können. Eine differenzierte Herangehensweise ist hierbei erforderlich, um Seesysteme im globalen Kontext angemessen zu analysieren. Ein Schlüssel zur Bewältigung dieser Herausforderung ist die datenwissenschaftliche Analyse von sedimentologischen Daten aus mehreren nördlichen Seesystemen. Diese Dissertation fokussiert sich dabei auf das Gebiet des nördlichen Eurasiens mit einem besonderen Fokus auf Seesystem in Russland (n=59). Die gesammelten sedimentologischen Daten für diese Doktorarbeit mussten hierfür zunächst standardisiert und homogenisiert werden. Hierfür wurde ein konzeptuelles Modell für die Integration und Standardisierung von heterogenen Multi-Proxy-Daten in ein relationales Datenbankverwaltungssystem (PostgreSQL) entworfen. Die Erstellung einer Datenbank aus der gesammelten Datenkollektion ermöglichte die numerische, vergleichende Analyse zwischen räumlich getrennten Seen als auch zwischen verschiedenen Proxys. Eine Analyse von mehreren Seen erforderte zudem eine gemeinsame Analyseebene, welche wir durch die Umwandlung von einer Tiefenabhängigkeit zu Altersabhängigkeit der Proxywerte erreichten. Diese bedurfte aber, dass die zugehörigen Alter von Proxywerte von allen Seen mit demselben Verfahren einer Alterstiefenmodellsoftware berechnet werden müssen. Angesichts der weitreichenden Implikationen und potenziellen Fallstricke entwickelten wir den LANDO-Ansatz („Linked Age and Depth Modelling“). LANDO stellt eine innovative Integration mehrerer Alters-Tiefen-Modellierungssoftware in eine einheitliche, kohärente Plattform (Jupyter Notebook) dar. Neben seiner Fähigkeit, Daten von fünf renommierten Alters-Tiefen-Modellierungssoftware zu aggregieren, ermöglicht LANDO es den Nutzern auf einzigartige Weise, unbegründete Modellergebnisse anhand robuster geowissenschaftlicher Daten herauszufiltern. Unsere Methode ist nicht nur neuartig, sondern steigert auch signifikant die Genauigkeit und Zuverlässigkeit von Seeanalysen. Schlussendlich unter Berücksichtigung der vorangegangenen Schritte betrachtet die Doktorarbeit den Zusammenhang zwischen Kohlenstoff in Sedimenten und Temperatur über die letzten 21 000 Jahre. Zunächst nehmen wir an, dass es eine positive Korrelation zwischen Kohlenstoffakkumulation in Seen und modellierter Paläo-Temperatur gibt. Diese kann dank des homogenisierten Datensatzes von heterogenen Seen bestätigt werden, wenn auch die höchsten Temperaturen über unseren Betrachtungszeitraum nicht korrelieren mit den höchsten Kohlenstoffwerten. Wir gehen davon aus, dass schnelle Erwärmungsereignisse eher zu einer hohen Akkumulation beitragen, während bestehende Erwärmung eher zu einer Ausgasung von Kohlenstoff führt. In Anbetracht der aktuellen hohen Konzentration von Kohlenstoff in der Atmosphäre und der steigenden Temperaturen, können bei einem weiterführenden Klimawandel nördliche Seesysteme zu einem weiteren Anstieg von atmosphärischem Kohlenstoff führen (positive Feedbackschleife). Obwohl die bemerkenswerten Ergebnisse zeigen, dass unser Ansatz aus standardisierten Daten und LANDO zuverlässig ist, könnte eine größere Datenmenge das Vertrauen in die Ergebnisse noch weiter stärken. KW - Arcitc KW - lake systems KW - paleotemperature KW - carbon KW - climate data science KW - Paläolimnologie KW - Eurasien KW - Paläoklimatologie KW - Seesedimente KW - Klimadatenwissenschaften KW - Kohlenstoff Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-636554 ER - TY - JOUR A1 - Glückler, Ramesh A1 - Geng, Rongwei A1 - Grimm, Lennart A1 - Baisheva, Izabella A1 - Herzschuh, Ulrike A1 - Stoof-Leichsenring, Kathleen R. A1 - Kruse, Stefan A1 - Andreev, Andrej Aleksandrovic A1 - Pestryakova, Luidmila A1 - Dietze, Elisabeth T1 - Holocene wildfire and vegetation dynamics in Central Yakutia, Siberia, reconstructed from lake-sediment proxies JF - Frontiers in Ecology and Evolution N2 - Wildfires play an essential role in the ecology of boreal forests. In eastern Siberia, fire activity has been increasing in recent years, challenging the livelihoods of local communities. Intensifying fire regimes also increase disturbance pressure on the boreal forests, which currently protect the permafrost beneath from accelerated degradation. However, long-term relationships between changes in fire regime and forest structure remain largely unknown. We assess past fire-vegetation feedbacks using sedimentary proxy records from Lake Satagay, Central Yakutia, Siberia, covering the past c. 10,800 years. Results from macroscopic and microscopic charcoal analyses indicate high amounts of burnt biomass during the Early Holocene, and that the present-day, low-severity surface fire regime has been in place since c. 4,500 years before present. A pollen-based quantitative reconstruction of vegetation cover and a terrestrial plant record based on sedimentary ancient DNA metabarcoding suggest a pronounced shift in forest structure toward the Late Holocene. Whereas the Early Holocene was characterized by postglacial open larch-birch woodlands, forest structure changed toward the modern, mixed larch-dominated closed-canopy forest during the Mid-Holocene. We propose a potential relationship between open woodlands and high amounts of burnt biomass, as well as a mediating effect of dense larch forest on the climate-driven intensification of fire regimes. Considering the anticipated increase in forest disturbances (droughts, insect invasions, and wildfires), higher tree mortality may force the modern state of the forest to shift toward an open woodland state comparable to the Early Holocene. Such a shift in forest structure may result in a positive feedback on currently intensifying wildfires. These new long-term data improve our understanding of millennial-scale fire regime changes and their relationships to changes of vegetation in Central Yakutia, where the local population is already being confronted with intensifying wildfire seasons. KW - fire KW - larch KW - boreal KW - forest KW - Russia KW - charcoal KW - pollen KW - ancient DNA Y1 - 2022 U6 - https://doi.org/10.3389/fevo.2022.962906 SN - 2296-701X VL - 10 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Inceoglu, Fadil A1 - Shprits, Yuri A1 - Heinemann, Stephan G. A1 - Bianco, Stefano T1 - Identification of coronal holes on AIA/SDO images using unsupervised machine learning JF - The astrophysical journal : an international review of spectroscopy and astronomical physics N2 - Through its magnetic activity, the Sun governs the conditions in Earth's vicinity, creating space weather events, which have drastic effects on our space- and ground-based technology. One of the most important solar magnetic features creating the space weather is the solar wind that originates from the coronal holes (CHs). The identification of the CHs on the Sun as one of the source regions of the solar wind is therefore crucial to achieve predictive capabilities. In this study, we used an unsupervised machine-learning method, k-means, to pixel-wise cluster the passband images of the Sun taken by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory in 171, 193, and 211 angstrom in different combinations. Our results show that the pixel-wise k-means clustering together with systematic pre- and postprocessing steps provides compatible results with those from complex methods, such as convolutional neural networks. More importantly, our study shows that there is a need for a CH database where a consensus about the CH boundaries is reached by observers independently. This database then can be used as the "ground truth," when using a supervised method or just to evaluate the goodness of the models. Y1 - 2022 U6 - https://doi.org/10.3847/1538-4357/ac5f43 SN - 1538-4357 VL - 930 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Geng, Rongwei A1 - Andreev, Andrei A1 - Kruse, Stefan A1 - Heim, Birgit A1 - van Geffen, Femke A1 - Pestryakova, Luidmila A1 - Zakharov, Evgenii A1 - Troeva, Elena I. A1 - Shevtsova, Iuliia A1 - Li, Furong A1 - Zhao, Yan A1 - Herzschuh, Ulrike T1 - Modern pollen assemblages from lake sediments and soil in East Siberia and relative pollen productivity estimates for Major Taxa JF - Frontiers in Ecology and Evolution N2 - Modern pollen-vegetation-climate relationships underpin palaeovegetation and palaeoclimate reconstructions from fossil pollen records. East Siberia is an ideal area for investigating the relationships between modern pollen assemblages and near natural vegetation under cold continental climate conditions. Reliable pollen-based quantitative vegetation and climate reconstructions are still scarce due to the limited number of modern pollen datasets. Furthermore, differences in pollen representation of samples from lake sediments and soils are not well understood. Here, we present a new pollen dataset of 48 moss/soil and 24 lake surface-sediment samples collected in Chukotka and central Yakutia in East Siberia. The pollen-vegetation-climate relationships were investigated by ordination analyses. Generally, tundra and taiga vegetation types can be well distinguished in the surface pollen assemblages. Moss/soil and lake samples contain generally similar pollen assemblages as revealed by a Procrustes comparison with some exceptions. Overall, modern pollen assemblages reflect the temperature and precipitation gradients in the study areas as revealed by constrained ordination analysis. We estimate the relative pollen productivity (RPP) of major taxa and the relevant source area of pollen (RSAP) for moss/soil samples from Chukotka and central Yakutia using Extended R-Value (ERV) analysis. The RSAP of the tundra-forest transition area in Chukotka and taiga area in central Yakutia are ca. 1300 and 360 m, respectively. For Chukotka, RPPs relative to both Poaceae and Ericaceae were estimated while RPPs for central Yakutia were relative only to Ericaceae. Relative to Ericaceae (reference taxon, RPP = 1), Larix, Betula, Picea, and Pinus are overrepresented while Alnus, Cyperaceae, Poaceae, and Salix are underrepresented in the pollen spectra. Our estimates are in general agreement with previously published values and provide the basis for reliable quantitative reconstructions of East Siberian vegetation. KW - modern pollen assemblages KW - pollen-vegetation-climate relationships KW - East Siberia KW - tundra KW - taiga KW - relative pollen productivity KW - quantitative vegetation reconstruction Y1 - 2022 U6 - https://doi.org/10.3389/fevo.2022.837857 SN - 2296-701X VL - 10 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Li, Wenjia A1 - Tian, Fang A1 - Rudaya, Natalya A. A1 - Herzschuh, Ulrike A1 - Cao, Xianyong T1 - Pollen-based holocene thawing-history of permafrost in Northern Asia and its potential impacts on climate change JF - Frontiers in Ecology and Evolution N2 - As the recent permafrost thawing of northern Asia proceeds due to anthropogenic climate change, precise and detailed palaeoecological records from past warm periods are essential to anticipate the extent of future permafrost variations. Here, based on the modern relationship between permafrost and vegetation (represented by pollen assemblages), we trained a Random Forest model using pollen and permafrost data and verified its reliability to reconstruct the history of permafrost in northern Asia during the Holocene. An early Holocene (12-8 cal ka BP) strong thawing trend, a middle-to-late Holocene (8-2 cal ka BP) relatively slow thawing trend, and a late Holocene freezing trend of permafrost in northern Asia are consistent with climatic proxies such as summer solar radiation and Northern Hemisphere temperature. The extensive distribution of permafrost in northern Asia inhibited the spread of evergreen coniferous trees during the early Holocene warming and might have decelerated the enhancement of the East Asian summer monsoon (EASM) by altering hydrological processes and albedo. Based on these findings, we suggest that studies of the EASM should consider more the state of permafrost and vegetation in northern Asia, which are often overlooked and may have a profound impact on climate change in this region. KW - pollen KW - Random Forest KW - Siberia KW - East Asian summer monsoon KW - permafrost Y1 - 2022 U6 - https://doi.org/10.3389/fevo.2022.894471 SN - 2296-701X VL - 10 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Öztürk, Ugur A1 - Bozzolan, Elisa A1 - Holcombe, Elizabeth A. A1 - Shukla, Roopam A1 - Pianosi, Francesca A1 - Wagener, Thorsten T1 - How climate change and unplanned urban sprawl bring more landslides JF - Nature : the international weekly journal of science N2 - More settlements will suffer as heavy rains and unregulated construction destabilize slopes in the tropics, models show. KW - Geophysics KW - Engineering KW - Climate change KW - Policy Y1 - 2022 U6 - https://doi.org/10.1038/d41586-022-02141-9 SN - 0028-0836 SN - 1476-4687 VL - 608 IS - 7922 SP - 262 EP - 265 PB - Nature portfolio CY - Berlin ER - TY - JOUR A1 - Song, Lina A1 - Jie, Dongmei A1 - Gao, Guizai A1 - Liu, Lidan A1 - Liu, Hongyan A1 - Li, Dehui A1 - Liu, Ying T1 - Application of a topsoil phytolith dataset to quantitative paleoclimate reconstruction in Northeast China JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - Although phytoliths are recognized as an important proxy for paleoenvironmental reconstruction, the quantitative relationship between phytoliths and climate is still debated. In order to provide an improved basis for phytolith-based paleoclimate reconstructions, a representative modern phytolith dataset is essential. Here, we synthesize a modern topsoil phytolith dataset for Northeast China, analyze its climatic significance, and apply it to a fossil phytolith series from the Hani peat core in Northeast China. The dataset comprises 660 topsoil phytolith assemblages from 289 sample sites. We compiled modern meteorological data to assess the quantitative relationship between the phytolith assemblages and climatic variables. Detrended correspondence analysis (DCA) and Redundancy analysis (RDA) were used to determine the dominant climatic variable influencing the phytolith distributions. The results showed that mean annual temperature (MAT) is the dominant variable controlling the spatial distribution of phytoliths, accounting for 8.91% of the total variance. Transfer function based on inverse deshrinking locally-weighted weighted averaging (LWWA_Inv) was developed for MAT (R-_boot(2) = 0.86, RMSEP = 1.02 degrees C). Applying the LWWA_Inv transfer function to fossil phytolith records from the Hani peat core enables quantitative inferences to be made about Holocene climate changes in Northeast China. Overall, combined with the LWWA_Inv method, the topsoil phytolith dataset of Northeast China can be used for reliable quantitative MAT reconstruction. KW - Phytoliths KW - Northeast China KW - Transfer function KW - paleoclimate KW - reconstruction Y1 - 2022 U6 - https://doi.org/10.1016/j.palaeo.2022.111108 SN - 0031-0182 SN - 1872-616X VL - 601 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Steirou, Eva A1 - Gerlitz, Lars A1 - Sun, Xun A1 - Apel, Heiko A1 - Agarwal, Ankit A1 - Totz, Sonja Juliana A1 - Merz, Bruno T1 - Towards seasonal forecasting of flood probabilities in Europe using climate and catchment information JF - Scientific reports N2 - We investigate whether the distribution of maximum seasonal streamflow is significantly affected by catchment or climate state of the season/month ahead. We fit the Generalized Extreme Value (GEV) distribution to extreme seasonal streamflow for around 600 stations across Europe by conditioning the GEV location and scale parameters on 14 indices, which represent the season-ahead climate or catchment state. The comparison of these climate-informed models with the classical GEV distribution, with time-constant parameters, suggests that there is a substantial potential for seasonal forecasting of flood probabilities. The potential varies between seasons and regions. Overall, the season-ahead catchment wetness shows the highest potential, although climate indices based on large-scale atmospheric circulation, sea surface temperature or sea ice concentration also show some skill for certain regions and seasons. Spatially coherent patterns and a substantial fraction of climate-informed models are promising signs towards early alerts to increase flood preparedness already a season ahead. Y1 - 2022 U6 - https://doi.org/10.1038/s41598-022-16633-1 SN - 2045-2322 VL - 12 IS - 1 PB - Nature portfolio CY - Berlin ER - TY - JOUR A1 - Astudillo-Sotomayor, Luis A1 - Jara Muñoz, Julius A1 - Melnick, Daniel A1 - Cortés‐Aranda, Joaquín A1 - Tassara, Andrés A1 - Strecker, Manfred T1 - Fast Holocene slip and localized strain along the Liquiñe-Ofqui strike-slip fault system, Chile JF - Scientific reports N2 - In active tectonic settings dominated by strike-slip kinematics, slip partitioning across subparallel faults is a common feature; therefore, assessing the degree of partitioning and strain localization is paramount for seismic hazard assessments. Here, we estimate a slip rate of 18.8 +/- 2.0 mm/year over the past 9.0 +/- 0.1 ka for a single strand of the Liquirie-Ofqui Fault System, which straddles the Main Cordillera in Southern Chile. This Holocene rate accounts for similar to 82% of the trench-parallel component of oblique plate convergence and is similar to million-year estimates integrated over the entire fault system. Our results imply that strain localizes on a single fault at millennial time scale but over longer time scales strain localization is not sustained. The fast millennial slip rate in the absence of historical Mw> 6.5 earthquakes along the Liquine-Ofqui Fault System implies either a component of aseismic slip or Mw similar to 7 earthquakes involving multi-trace ruptures and > 150-year repeat times. Our results have implications for the understanding of strike-slip fault system dynamics within volcanic arcs and seismic hazard assessments. KW - Geodynamics KW - Geomorphology KW - Tectonics Y1 - 2021 U6 - https://doi.org/10.1038/s41598-021-85036-5 SN - 2045-2322 VL - 11 IS - 1 PB - Macmillan Publishers Limited, part of Springer Nature CY - London ER - TY - JOUR A1 - López-Comino, José Ángel A1 - Cesca, Simone A1 - Niemz, Peter A1 - Dahm, Torsten A1 - Zang, Arno T1 - Rupture directivity in 3D inferred from acoustic emissions events in a mine-scale hydraulic fracturing experiment JF - Frontiers in Earth Science N2 - Rupture directivity, implying a predominant earthquake rupture propagation direction, is typically inferred upon the identification of 2D azimuthal patterns of seismic observations for weak to large earthquakes using surface-monitoring networks. However, the recent increase of 3D monitoring networks deployed in the shallow subsurface and underground laboratories toward the monitoring of microseismicity allows to extend the directivity analysis to 3D modeling, beyond the usual range of magnitudes. The high-quality full waveforms recorded for the largest, decimeter-scale acoustic emission (AE) events during a meter-scale hydraulic fracturing experiment in granites at similar to 410 m depth allow us to resolve the apparent durations observed at each AE sensor to analyze 3D-directivity effects. Unilateral and (asymmetric) bilateral ruptures are then characterized by the introduction of a parameter kappa, representing the angle between the directivity vector and the station vector. While the cloud of AE activity indicates the planes of the hydrofractures, the resolved directivity vectors show off-plane orientations, indicating that rupture planes of microfractures on a scale of centimeters have different geometries. Our results reveal a general alignment of the rupture directivity with the orientation of the minimum horizontal stress, implying that not only the slip direction but also the fracture growth produced by the fluid injections is controlled by the local stress conditions. KW - directivity KW - earthquake source KW - induced seismicity KW - hydraulic KW - fracturing KW - acoustic emissions Y1 - 2021 U6 - https://doi.org/10.3389/feart.2021.670757 SN - 2296-6463 VL - 9 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Esfahani, Reza Dokht Dolatabadi A1 - Gholami, Ali A1 - Ohrnberger, Matthias T1 - An inexact augmented Lagrangian method for nonlinear dispersion-curve inversion using Dix-type global linear approximation JF - Geophysics : a journal of general and applied geophysics N2 - 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. KW - surface wave KW - nonlinear KW - inversion KW - modeling KW - finite element Y1 - 2020 U6 - https://doi.org/10.1190/geo2019-0717.1 SN - 0016-8033 SN - 1942-2156 VL - 85 IS - 3 SP - EN77 EP - EN85 PB - GeoScienceWorld CY - Tulsa, Okla. ER - TY - JOUR A1 - Spallanzani, Roberta A1 - Koga, Kenneth T. A1 - Cichy, Sarah B. A1 - Wiedenbeck, Michael A1 - Schmidt, Burkhard C. A1 - Oelze, Marcus A1 - Wilke, Max T1 - Lithium and boron diffusivity and isotopic fractionation in hydrated rhyolitic melts JF - Contributions to mineralogy and petrology N2 - Lithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. In this study, we determine the diffusivity and isotopic fractionation of Li and B in hydrous silicate melts. Two glasses were synthesized with the same rhyolitic composition (4.2 wt% water), having different Li and B contents; these were studied in diffusion-couple experiments that were performed using an internally heated pressure vessel, operated at 300 MPa in the temperature range 700-1250 degrees C for durations from 0 s to 24 h. From this we determined activation energies for Li and B diffusion of 57 +/- 4 kJ/mol and 152 +/- 15 kJ/mol with pre-exponential factors of 1.53 x 10(-7) m(2)/s and 3.80 x 10(-8) m(2)/s, respectively. Lithium isotopic fractionation during diffusion gave beta values between 0.15 and 0.20, whereas B showed no clear isotopic fractionation. Our Li diffusivities and isotopic fractionation results differ somewhat from earlier published values, but overall confirm that Li diffusivity increases with water content. Our results on B diffusion show that similarly to Li, B mobility increases in the presence of water. By applying the Eyring relation, we confirm that B diffusivity is limited by viscous flow in silicate melts. Our results on Li and B diffusion present a new tool for understanding degassing-related processes, offering a potential geospeedometer to measure volcanic ascent rates. KW - stable isotopes KW - diffusion KW - isotopic fractionation KW - hydrated silicate KW - melts Y1 - 2022 U6 - https://doi.org/10.1007/s00410-022-01937-2 SN - 0010-7999 SN - 1432-0967 VL - 177 IS - 8 PB - Springer CY - New York ER - TY - JOUR A1 - Kotha, Sreeram Reddy A1 - Weatherill, Graeme A1 - Bindi, Dino A1 - Cotton, Fabrice T1 - Near-source magnitude scaling of spectral accelerations BT - analysis and update of Kotha et al. (2020) model JF - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering N2 - Ground-motion models (GMMs) are often used to predict the random distribution of Spectral accelerations (SAs) at a site due to a nearby earthquake. In probabilistic seismic hazard and risk assessment, large earthquakes occurring close to a site are considered as critical scenarios. GMMs are expected to predict realistic SAs with low within-model uncertainty (sigma(mu)) for such rare scenarios. However, the datasets used to regress GMMs are usually deficient of data from critical scenarios. The (Kotha et al., A Regionally Adaptable Ground-Motion Model for Shallow Crustal Earthquakes in Europe Bulletin of Earthquake Engineering 18:4091-4125, 2020) GMM developed from the Engineering strong motion (ESM) dataset was found to predict decreasing short-period SAs with increasing M-W >= M-h = 6.2, and with large sigma(mu) at near-source distances <= 30km. In this study, we updated the parametrisation of the GMM based on analyses of ESM and the Near source strong motion (NESS) datasets. With M-h = 5.7, we could rectify the M-W scaling issue, while also reducing sigma(mu). at M-W >= M-h. We then evaluated the GMM against NESS data, and found that the SAs from a few large, thrust-faulting events in California, New Zealand, Japan, and Mexico are significantly higher than GMM median predictions. However, recordings from these events were mostly made on soft-soil geology, and contain anisotropic pulse-like effects. A more thorough non-ergodic treatment of NESS was not possible because most sites sampled unique events in very diverse tectonic environments. We provide an updated set of GMM coefficients,sigma(mu), and heteroscedastic variance models; while also cautioning against its application for M-W <= 4 in low-moderate seismicity regions without evaluating the homogeneity of M-W estimates between pan-European ESM and regional datasets. KW - Ground-motion model KW - Spectral accelerations KW - Magnitude scalin KW - Near-source saturation KW - Within-model uncertainty KW - Heteroscedastic KW - variability Y1 - 2022 U6 - https://doi.org/10.1007/s10518-021-01308-5 SN - 1570-761X SN - 1573-1456 VL - 20 IS - 3 SP - 1343 EP - 1370 PB - Springer CY - Dordrecht ER - TY - THES A1 - Koyan, Philipp T1 - 3D attribute analysis and classification to interpret ground-penetrating radar (GPR) data collected across sedimentary environments: Synthetic studies and field examples T1 - 3D Attributanalyse und -klassifizierung zur Interpretation von Georadar-Daten in sedimentären Umgebungen: Synthetische Studien und Feldbeispiele N2 - Die Untersuchung des oberflächennahen Untergrundes erfolgt heutzutage bei Frage- stellungen aus den Bereichen des Bauwesens, der Archäologie oder der Geologie und Hydrologie oft mittels zerstörungsfreier beziehungsweise zerstörungsarmer Methoden der angewandten Geophysik. Ein Bereich, der eine immer zentralere Rolle in Forschung und Ingenieurwesen einnimmt, ist die Untersuchung von sedimentären Umgebungen, zum Beispiel zur Charakterisierung oberflächennaher Grundwassersysteme. Ein in diesem Kontext häufig eingesetztes Verfahren ist das des Georadars (oftmals GPR - aus dem Englischen ground-penetrating radar). Dabei werden kurze elektromagnetische Impulse von einer Antenne in den Untergrund ausgesendet, welche dort wiederum an Kontrasten der elektromagnetischen Eigenschaften (wie zum Beispiel an der Grundwasseroberfläche) reflektiert, gebrochen oder gestreut werden. Eine Empfangsantenne zeichnet diese Signale in Form derer Amplituden und Laufzeiten auf. Eine Analyse dieser aufgezeichneten Signale ermöglicht Aussagen über den Untergrund, beispielsweise über die Tiefenlage der Grundwasseroberfläche oder die Lagerung und Charakteristika oberflächennaher Sedimentschichten. Dank des hohen Auflösungsvermögens der GPR-Methode sowie stetiger technologischer Entwicklungen erfolgt heutzutage die Aufzeichnung von GPR- Daten immer häufiger in 3D. Trotz des hohen zeitlichen und technischen Aufwandes für die Datenakquisition und -bearbeitung werden die resultierenden 3D-Datensätze, welche den Untergrund hochauflösend abbilden, typischerweise von Hand interpretiert. Dies ist in der Regel ein äußerst zeitaufwendiger Analyseschritt. Daher werden oft repräsentative 2D-Schnitte aus dem 3D-Datensatz gewählt, in denen markante Reflektionsstrukuren markiert werden. Aus diesen Strukturen werden dann sich ähnelnde Bereiche im Untergrund als so genannte Radar-Fazies zusammengefasst. Die anhand von 2D-Schnitten erlangten Resultate werden dann als repräsentativ für die gesamte untersuchte Fläche angesehen. In dieser Form durchgeführte Interpretationen sind folglich oft unvollständig sowie zudem in hohem Maße von der Expertise der Interpretierenden abhängig und daher in der Regel nicht reproduzierbar. Eine vielversprechende Alternative beziehungsweise Ergänzung zur manuellen In- terpretation ist die Verwendung von so genannten GPR-Attributen. Dabei werden nicht die aufgezeichneten Daten selbst, sondern daraus abgeleitete Größen, welche die markanten Reflexionsstrukturen in 3D charakterisieren, zur Interpretation herangezogen. In dieser Arbeit wird anhand verschiedener Feld- und Modelldatensätze untersucht, welche Attribute sich dafür insbesondere eignen. Zudem zeigt diese Arbeit, wie ausgewählte Attribute mittels spezieller Bearbeitungs- und Klassifizierungsmethoden zur Erstellung von 3D-Faziesmodellen genutzt werden können. Dank der Möglichkeit der Erstellung so genannter attributbasierter 3D-GPR-Faziesmodelle können zukünftige Interpretationen zu gewissen Teilen automatisiert und somit effizienter durchgeführt werden. Weiterhin beschreiben die so erhaltenen Resultate den untersuchten Untergrund in reproduzierbarer Art und Weise sowie umfänglicher als es bisher mittels manueller Interpretationsmethoden typischerweise möglich war. N2 - Today, near-surface investigations are frequently conducted using non-destructive or minimally invasive methods of applied geophysics, particularly in the fields of civil engineering, archaeology, geology, and hydrology. One field that plays an increasingly central role in research and engineering is the examination of sedimentary environments, for example, for characterizing near-surface groundwater systems. A commonly employed method in this context is ground-penetrating radar (GPR). In this technique, short electromagnetic pulses are emitted into the subsurface by an antenna, which are then reflected, refracted, or scattered at contrasts in electromagnetic properties (such as the water table). A receiving antenna records these signals in terms of their amplitudes and travel times. Analysis of the recorded signals allows for inferences about the subsurface, such as the depth of the groundwater table or the composition and characteristics of near-surface sediment layers. Due to the high resolution of the GPR method and continuous technological advancements, GPR data acquisition is increasingly performed in three-dimensional (3D) fashion today. Despite the considerable temporal and technical efforts involved in data acquisition and processing, the resulting 3D data sets (providing high-resolution images of the subsurface) are typically interpreted manually. This is generally an extremely time-consuming analysis step. Therefore, representative 2D sections highlighting distinctive reflection structures are often selected from the 3D data set. Regions showing similar structures are then grouped into so-called radar facies. The results obtained from 2D sections are considered representative of the entire investigated area. Interpretations conducted in this manner are often incomplete and highly dependent on the expertise of the interpreters, making them generally non-reproducible. A promising alternative or complement to manual interpretation is the use of GPR attributes. Instead of using the recorded data directly, derived quantities characterizing distinctive reflection structures in 3D are applied for interpretation. Using various field and synthetic data sets, this thesis investigates which attributes are particularly suitable for this purpose. Additionally, the study demonstrates how selected attributes can be utilized through specific processing and classification methods to create 3D facies models. The ability to generate attribute-based 3D GPR facies models allows for partially automated and more efficient interpretations in the future. Furthermore, the results obtained in this manner describe the subsurface in a reproducible and more comprehensive manner than what has typically been achievable through manual interpretation methods. KW - ground-penetrating radar KW - sedimentary environments KW - 3D KW - applied geophysics KW - near-surface geophysics KW - Georadar KW - sedimentäre Systeme KW - angewandte Geophysik KW - oberflächennahe Geophysik KW - Attribute KW - attributes KW - geophysics KW - Geophysik Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-639488 ER - TY - JOUR A1 - Merz, Bruno A1 - Basso, Stefano A1 - Fischer, Svenja A1 - Lun, David A1 - Bloeschl, Guenter A1 - Merz, Ralf A1 - Guse, Bjorn A1 - Viglione, Alberto A1 - Vorogushyn, Sergiy A1 - Macdonald, Elena A1 - Wietzke, Luzie A1 - Schumann, Andreas T1 - Understanding heavy tails of flood peak distributions JF - Water resources research N2 - Statistical distributions of flood peak discharge often show heavy tail behavior, that is, extreme floods are more likely to occur than would be predicted by commonly used distributions that have exponential asymptotic behavior. This heavy tail behavior may surprise flood managers and citizens, as human intuition tends to expect light tail behavior, and the heaviness of the tails is very difficult to predict, which may lead to unnecessarily high flood damage. Despite its high importance, the literature on the heavy tail behavior of flood distributions is rather fragmented. In this review, we provide a coherent overview of the processes causing heavy flood tails and the implications for science and practice. Specifically, we propose nine hypotheses on the mechanisms causing heavy tails in flood peak distributions related to processes in the atmosphere, the catchment, and the river system. We then discuss to which extent the current knowledge supports or contradicts these hypotheses. We also discuss the statistical conditions for the emergence of heavy tail behavior based on derived distribution theory and relate them to the hypotheses and flood generation mechanisms. We review the degree to which the heaviness of the tails can be predicted from process knowledge and data. Finally, we recommend further research toward testing the hypotheses and improving the prediction of heavy tails. KW - extreme events KW - flood frequency KW - flood risk KW - upper tail Y1 - 2022 U6 - https://doi.org/10.1029/2021WR030506 SN - 0043-1397 SN - 1944-7973 VL - 58 IS - 6 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Krstulović, Marija A1 - Rosa, Angelika D. A1 - Ferreira Sanchez, Dario A1 - Libon, Lélia A1 - Albers, Christian A1 - Merkulova, Margarita A1 - Grolimund, Daniel A1 - Irifune, Tetsuo A1 - Wilke, Max T1 - Effect of temperature on the densification of silicate melts to lower earth's mantle conditions JF - Physics of the earth and planetary interiors N2 - Physical properties of silicate melts play a key role for global planetary dynamics, controlling for example volcanic eruption styles, mantle convection and elemental cycling in the deep Earth. They are significantly modified by structural changes at the atomic scale due to external parameters such as pressure and temperature or due to chemistry. Structural rearrangements such as 4- to 6-fold coordination change of Si with increasing depth may profoundly influence melt properties, but have so far mostly been studied at ambient temperature due to experimental difficulties. In order to investigate the structural properties of silicate melts and their densification mechanisms at conditions relevant to the deep Earth's interior, we studied haplo basaltic glasses and melts (albite-diopside composition) at high pressure and temperature conditions in resistively and laser-heated diamond anvil cells using X-ray absorption near edge structure spectroscopy. Samples were doped with 10 wt% of Ge, which is accessible with this experimental technique and which commonly serves as a structural analogue for the network forming cation Si. We acquired spectra on the Ge K edge up to 48 GPa and 5000 K and derived the average Ge-O coordination number NGe-O, and bond distance RGe-O as functions of pressure. Our results demonstrate a continuous transformation from tetrahedral to octahedral coordination between ca. 5 and 30 GPa at ambient temperature. Above 1600 K the data reveal a reduction of the pressure needed to complete conversion to octahedral coordination by ca. 30 %. The results allow us to determine the influence of temperature on the Si coordination number changes in natural melts in the Earth's interior. We propose that the complete transition to octahedral coordination in basaltic melts is reached at about 40 GPa, corresponding to a depth of ca. 1200 km in the uppermost lower mantle. At the core-mantle boundary (2900 km, 130 GPa, 3000 K) the existence of non-buoyant melts has been proposed to explain observed low seismic wave velocity features. Our results highlight that the melt composition can affect the melt density at such extreme conditions and may strongly influence the structural response. KW - Silicate melts KW - Densification KW - High pressure and high temperature; KW - XANES KW - Coordination number KW - Ultra-low velocity zones Y1 - 2022 U6 - https://doi.org/10.1016/j.pepi.2021.106823 SN - 0031-9201 SN - 1872-7395 VL - 323 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Nooshiri, Nima A1 - Bean, Christopher J. A1 - Dahm, Torsten A1 - Grigoli, Francesco A1 - Kristjansdottir, Sigriour A1 - Obermann, Anne A1 - Wiemer, Stefan T1 - A multibranch, multitarget neural network for rapid point-source inversion in a microseismic environment BT - examples from the Hengill Geothermal Field, Iceland JF - Geophysical journal international N2 - Despite advanced seismological techniques, automatic source characterization for microseismic earthquakes remains difficult and challenging since current inversion and modelling of high-frequency signals are complex and time consuming. For real-time applications such as induced seismicity monitoring, the application of standard methods is often not fast enough for true complete real-time information on seismic sources. In this paper, we present an alternative approach based on recent advances in deep learning for rapid source-parameter estimation of microseismic earthquakes. The seismic inversion is represented in compact form by two convolutional neural networks, with individual feature extraction, and a fully connected neural network, for feature aggregation, to simultaneously obtain full moment tensor and spatial location of microseismic sources. Specifically, a multibranch neural network algorithm is trained to encapsulate the information about the relationship between seismic waveforms and underlying point-source mechanisms and locations. The learning-based model allows rapid inversion (within a fraction of second) once input data are available. A key advantage of the algorithm is that it can be trained using synthetic seismic data only, so it is directly applicable to scenarios where there are insufficient real data for training. Moreover, we find that the method is robust with respect to perturbations such as observational noise and data incompleteness (missing stations). We apply the new approach on synthesized and example recorded small magnitude (M <= 1.6) earthquakes at the Hellisheioi geothermal field in the Hengill area, Iceland. For the examined events, the model achieves excellent performance and shows very good agreement with the inverted solutions determined through standard methodology. In this study, we seek to demonstrate that this approach is viable for microseismicity real-time estimation of source parameters and can be integrated into advanced decision-support tools for controlling induced seismicity. KW - Neural networks KW - fuzzy logic KW - Computational seismology KW - Induced seismicity KW - Earthquake source observations Y1 - 2021 U6 - https://doi.org/10.1093/gji/ggab511 SN - 0956-540X SN - 1365-246X VL - 229 IS - 2 SP - 999 EP - 1016 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Ezpeleta, Miguel A1 - Parra, Mauricio A1 - Collo, Gilda A1 - Wunderlin, Cecilia A1 - Borrego, Angeles G. A1 - Sobel, Edward A1 - Glodny, Johannes T1 - Thermochronometry unveils ancient thermal regimes in the NW Pampean Ranges, Argentina BT - from Mesozoic rifting to Miocene flat-slab subduction JF - Basin research N2 - Reconstructing thermal histories in thrust belts is commonly used to infer the age and rates of thrusting and hence the driving mechanisms of orogenesis. In areas where ancient basins have been incorporated into the orogenic wedge, a quantitative reconstruction of the thermal history helps distinguish among potential mechanisms responsible for heating events. We present such a reconstruction for the Ischigualasto-Villa Union basin in the western Pampean Ranges of Argentina, where Triassic rifting and late Cretaceous-Cenozoic retroarc foreland basin development has been widely documented, including Miocene flat-slab subduction. We report results of organic and inorganic thermal indicators acquired along three stratigraphic sections, including vitrinite reflectance and X-ray diffractometry in claystones and new thermochronological [(apatite fission-track and apatite and zircon [U-Th]/He)] analyses. Despite up to 5 km-thick Cenozoic overburden and unlike previously thought, the thermal peak in the basin is not due to Cenozoic burial but occurred in the Triassic, associated with a high heat flow of up to 90 mWm(-2) and <2 km of burial, which heated the base of the Triassic strata to similar to 160 degrees C. Following exhumation, attested by the development of an unconformity between the Triassic and Late-Cretaceous-Cenozoic sequences, Cenozoic re-burial increased the temperature to similar to 110 degrees C at the base of the Triassic section and only similar to 50 degrees C 7 km upsection, suggesting a dramatic decrease in the thermal gradient. The onset of Cenozoic cooling occurred at similar to 10(-8) Ma, concomitant with sediment accumulation and thus preceding the latest Miocene onset of thrusting that has been independently documented by stratigraphic-cross-cutting relationships. We argue that the onset of cooling is associated with lithospheric refrigeration following establishment of flat-slab subduction, leading to the eastward displacement of the asthenospheric wedge beneath the South American plate. Our study places time and temperature constraints on flat-slab cooling that calls for a careful interpretation of exhumation signals in thrustbelts inferred from thermochronology only. KW - %Ro KW - Cenozoic flat-slab KW - Ischigualasto-Villa Union Basin KW - thermochronological modelling (AFT, AHe and ZHe) KW - Triassic rifting KW - XRD in the clay fraction KW - heat flow KW - burial Y1 - 2022 U6 - https://doi.org/10.1111/bre.12693 SN - 0950-091X SN - 1365-2117 VL - 34 IS - 6 SP - 1983 EP - 2012 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Fernandez-Palomino, Carlos Antonio A1 - Hattermann, Fred A1 - Krysanova, Valentina A1 - Lobanova, Anastasia A1 - Vega-Jacome, Fiorella A1 - Lavado, Waldo A1 - Santini, William A1 - Aybar, Cesar A1 - Bronstert, Axel T1 - A novel high-resolution gridded precipitation dataset for peruvian and ecuadorian watersheds BT - development and hydrological evaluation JF - Journal of hydrometeorology N2 - A novel approach for estimating precipitation patterns is developed here and applied to generate a new hydrologically corrected daily precipitation dataset, called RAIN4PE (Rain for Peru and Ecuador), at 0.1 degrees spatial resolution for the period 1981-2015 covering Peru and Ecuador. It is based on the application of 1) the random forest method to merge multisource precipitation estimates (gauge, satellite, and reanalysis) with terrain elevation, and 2) observed and modeled streamflow data to first detect biases and second further adjust gridded precipitation by inversely applying the simulated results of the ecohydrological model SWAT (Soil and Water Assessment Tool). Hydrological results using RAIN4PE as input for the Peruvian and Ecuadorian catchments were compared against the ones when feeding other uncorrected (CHIRP and ERA5) and gauge-corrected (CHIRPS, MSWEP, and PISCO) precipitation datasets into the model. For that, SWAT was calibrated and validated at 72 river sections for each dataset using a range of performance metrics, including hydrograph goodness of fit and flow duration curve signatures. Results showed that gauge-corrected precipitation datasets outperformed uncorrected ones for streamflow simulation. However, CHIRPS, MSWEP, and PISCO showed limitations for streamflow simulation in several catchments draining into the Pacific Ocean and the Amazon River. RAIN4PE provided the best overall performance for streamflow simulation, including flow variability (low, high, and peak flows) and water budget closure. The overall good performance of RAIN4PE as input for hydrological modeling provides a valuable criterion of its applicability for robust countrywide hydrometeorological applications, including hydroclimatic extremes such as droughts and floods. Significance StatementWe developed a novel precipitation dataset RAIN4PE for Peru and Ecuador by merging multisource precipitation data (satellite, reanalysis, and ground-based precipitation) with terrain elevation using the random forest method. Furthermore, RAIN4PE was hydrologically corrected using streamflow data in watersheds with precipitation underestimation through reverse hydrology. The results of a comprehensive hydrological evaluation showed that RAIN4PE outperformed state-of-the-art precipitation datasets such as CHIRP, ERA5, CHIRPS, MSWEP, and PISCO in terms of daily and monthly streamflow simulations, including extremely low and high flows in almost all Peruvian and Ecuadorian catchments. This underlines the suitability of RAIN4PE for hydrometeorological applications in this region. Furthermore, our approach for the generation of RAIN4PE can be used in other data-scarce regions. KW - Amazon region KW - Complex terrain KW - South America KW - Streamflow KW - Precipitation KW - Hydrology KW - Water budget / balance KW - Inverse methods KW - Mountain meteorology KW - Machine learning Y1 - 2022 U6 - https://doi.org/10.1175/JHM-D-20-0285.1 SN - 1525-755X SN - 1525-7541 VL - 23 IS - 3 SP - 309 EP - 336 PB - American Meteorological Soc. CY - Boston ER -