Article
Multidisciplinary Sciences
Thorne Lay, Stuart P. Nishenko
Summary: In the western South America, six very large-magnitude earthquakes have occurred so far in this century. The history of previous earthquakes in each source region has led to the identification of seismic gaps as potential hosts for future large earthquakes. The deployment of monitoring instruments has enhanced our understanding of the faulting processes and the accumulation of slip deficit on the megathrust fault. These findings provide valuable information for assessing the current earthquake hazard along the South American subduction zone.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Geochemistry & Geophysics
Mario D'Acquisto, Taco Broerse, Celine P. Marsman, Rob Govers
Summary: We analyzed the results of GNSS measurements with sub-meter accuracy in South America, Southeast Asia, and northern Japan to understand the deformation of overriding plates during megathrust earthquakes. Our findings show that interseismic velocities decrease with distance from the trench, reaching a hurdle where the gradient becomes lower and velocities are small. These hurdles are located 500-1000 km away from the trench and are associated with significant coseismic displacements during major earthquakes. Finite element models of the earthquake cycle suggest that the hurdles result from a contrast in the mechanical properties of the overriding plate, with a stiffer plate beyond the hurdler. Previous studies have found major tectonic or geological boundaries near these observed hurdles, indicating their significance.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Sam Wimpenny, Tim Craig, Savvas Marcou
Summary: Changes in intermediate-depth earthquake frequency provide insights into earthquake generation mechanisms in subducting slabs. This study shows that faults within the slab are relatively insensitive to static stress transfer, indicating they are far from their failure stress. Aftershock productivity also varies within slabs, suggesting spatially heterogeneous mechanisms, possibly related to dehydration-induced weakening.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
News Item
Geosciences, Multidisciplinary
Gregory A. Ruetenik
Summary: Deciphering mantle convection's impact on Earth's surface elevation is difficult, but a new study on Calabria's topographic evolution suggests it may have a dominant influence on mountain-building at subduction zones.
Article
Geosciences, Multidisciplinary
Roland Freisleben, Julius Jara-Munoz, Daniel Melnick, Jose Miguel Martinez, Manfred R. Strecker
Summary: Tectonically active coasts are characterized by multiple marine terraces formed by a combination of wave erosion, tectonic uplift, and sea-level oscillations. Our study of the marine terraces along the western coast of South America revealed a median elevation of 30.1 m, suggesting a median uplift rate of 0.22 m kyr(-1) over the past approximately 125 kyr. The patterns of terrace elevation and uplift rate exhibit different structures along the coast, with long-wavelength deformation possibly being controlled by deep-seated processes like subduction, while short-wavelength deformation may be associated with crustal faulting.
EARTH SYSTEM SCIENCE DATA
(2021)
Article
Geosciences, Multidisciplinary
Muhammad Taufiq Rafie, David P. Sahara, Phil R. Cummins, Wahyu Triyoso, Sri Widiyantoro
Summary: This study investigates the stress transfer from large subduction earthquakes to the Sumatran Fault. The results suggest that these earthquakes have caused stress accumulation along the southern part of the fault, indicating potential high earthquake hazard.
Article
Multidisciplinary Sciences
R. Plata-Martinez, S. Ide, M. Shinohara, E. S. Garcia, N. Mizuno, L. A. Dominguez, T. Taira, Y. Yamashita, A. Toh, T. Yamada, J. Real, A. Husker, V. M. Cruz-Atienza, Y. Ito
Summary: New offshore observations in the Guerrero seismic gap discovered shallow slow earthquakes, which suggest that a portion of the plate interface undergoes stable slip. This may explain the long return period of large earthquakes and why have previous large earthquakes not propagated into the gap.
NATURE COMMUNICATIONS
(2021)
Article
Geochemistry & Geophysics
Meng Sun, Maximiliano J. Bezada, John Cornthwaite, German A. Prieto, Fenglin Niu, Alan Levander
Summary: This study used seismic data and finite-frequency tomography models to reveal different subduction segments in northwestern South America, confirming the overlap zone between the Nazca and Caribbean plates proposed by previous studies. The Bucaramanga Nest within the Caribbean Plate coincides with slab bending, and elevated stresses are identified as a key factor in the high seismicity rates in the region.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Afsaneh Mohammadzaheri, Karin Sigloch, Kasra Hosseini, Mitchell G. Mihalynuk
Summary: In this study, the mantle structure beneath South America was analyzed using seismic tomography, revealing four high-velocity provinces interpreted as subducted lithosphere. These provinces provide insights into the geodynamic processes in the region over time.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Sebastian Arango-Serna, Leonardo Gallo, Jose H. Zambrano, Alejandro Cruz, Eimar Sandoval, Peter Thomson
Summary: The east of Cali is made up of loose sand deposits with high water table levels, resulting in cyclic liquefaction being a major hazard in the city. To study liquefiable soils under local seismogenic conditions, a seismic monitoring center was designed and implemented. The center has been built in two stages, with the first stage already operational and able to record earthquakes and verify the saturation of the potentially liquefiable layer. Ground motion sensors in the future will further enhance the understanding of shear strains and excess pore pressures in the soil deposit.
JOURNAL OF SEISMOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Florian Petersen, Dietrich Lange, Bo Ma, Ingo Grevemeyer, Jacob Geersen, Dirk Klaeschen, Eduardo Contreras-Reyes, Sergio Barrientos, Anne M. Trehu, Emilio Vera, Heidrun Kopp
Summary: The aftershock distribution of the 2014 Mw 8.1 Iquique earthquake offshore northern Chile suggests that seismic activity updip of the main earthquake area reflects active subduction erosion processes. The lack of sediment accretion and subduction erosion over millions of years has resulted in a very weak and aseismic frontal wedge. This study links shallow subduction zone seismicity to subduction erosion processes controlling the evolution of the overriding plate.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Marcelo Belentani Bianchi, Marcelo Assumpcao, Clinton Koch, Susan Beck
Summary: The Nazca plate subducting beneath South America results in a deeper 660 km discontinuity and a thicker mantle transition zone (MTZ). The variations in MTZ thickness can help determine the position of the slab. Research shows that the Nazca slab affects the MTZ in South America, indicating that the slab flattens near the 660 km discontinuity, lowering mantle temperature and thickening the MTZ.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2021)
Article
Geography, Physical
Junki Komori, Masanobu Shishikura, Ryosuke Ando, Yusuke Yokoyama, Yosuke Miyairi
Summary: This study quantitatively evaluated the emergence ages of tectonically uplifted marine terraces in central Japan. A new method was proposed to estimate the emergence ages of the terraces using Bayesian statistics and the temporal distribution of sample ages. The results showed variations in recurrence intervals of terrace-forming earthquakes and provided valuable information for subduction zone research and hazard assessments.
QUATERNARY SCIENCE REVIEWS
(2021)
Article
Geosciences, Multidisciplinary
Carlos Pena, Sabrina Metzger, Oliver Heidbach, Jonathan Bedford, Bodo Bookhagen, Marcos Moreno, Onno Oncken, Fabrice Cotton
Summary: Megathrust earthquakes can induce changes in stress and pore pressure in the lithosphere-asthenosphere system, which are transiently relaxed during the postseismic period. The relative contributions of afterslip, viscoelasticity, and poroelasticity to observed surface deformation in the early postseismic phase are unclear. By analyzing geodetic data and using a poro-viscoelastic forward model combined with an afterslip inversion, it was found that poroelastic effects better explain the observed surface uplift pattern near the region of maximum coseismic slip. Neglecting poroelasticity can cause significant alterations in the spatial distribution of afterslip. Additionally, shallow crustal aftershocks tend to occur in regions with increased postseismic pore-pressure changes, suggesting a possible mechanical coupling between these processes.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Alice R. Turner, Ana M. G. Ferreira, Andrea Berbellini, Nicolas Brantut, Manuele Faccenda, Elodie Kendall
Summary: This study investigates the rupture characteristics and propagation mechanisms of deep earthquakes using seismic waveforms. The results show that deep earthquakes have similar stress drops, spatial dimensions, and durations as crustal earthquakes, and exhibit high radiated efficiency. Comparisons with subduction models suggest that deep earthquakes and shallow earthquakes are controlled by the same physics in terms of rupture propagation.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Jannes Munchmeyer, Jack Woollam, Andreas Rietbrock, Frederik Tilmann, Dietrich Lange, Thomas Bornstein, Tobias Diehl, Carlo Giunchi, Florian Haslinger, Dario Jozinovic, Alberto Michelini, Joachim Saul, Hugo Soto
Summary: Deep learning models, such as EQTransformer, GPD, and PhaseNet, have shown the best performance in seismic event detection and phase picking. The study also reveals that models can be effectively transferred across regions with similar distances. The results and trained models are made accessible to end-users through the SeisBench framework for easy application.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Youqiang Yu, Frederik Tilmann, Dapeng Zhao, Stephen S. Gao, Kelly H. Liu
Summary: This study reveals that the Woodlark rift follows a passive model and is mainly driven by slab pull.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Molly D. O'Beirne, Robert Sparkes, Trinity L. Hamilton, Bart E. van Dongen, William P. Gilhooly, Josef P. Werne
Summary: Bacteriohopanepolyols (BHPs) are a diverse class of bacterial lipids that have the potential to serve as biomarkers for specific microbes, microbial processes, and environmental conditions. In this study, BHPs were analyzed in samples from the water column and upper sediments of Mahoney Lake in Canada. The distributions of BHPs varied in different water layers and environmental conditions. The study also revealed that BHPs in Mahoney Lake are most likely produced by bacteria belonging to Deltaproteobacteria, Chloroflexi, Planctomycetia, and Verrucomicrobia.
ORGANIC GEOCHEMISTRY
(2022)
Article
Geochemistry & Geophysics
Jack Woollam, Jannes Muenchmeyer, Frederik Tilmann, Andreas Rietbrock, Dietrich Lange, Thomas Bornstein, Tobias Diehl, Carlo Giunchi, Florian Haslinger, Dario Jozinovi, Alberto Michelini, Joachim Saul, Hugo Soto
Summary: Machine-learning methods have been widely used in seismology, but the current process of accessing benchmark datasets and models is time-consuming, which hinders the further development of machine learning techniques. To address this issue, we introduce SeisBench, an open-source framework that standardizes access to models and datasets and provides common processing and data augmentation operations. With SeisBench, seismologists can easily access various machine learning models and benchmark datasets.
SEISMOLOGICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Antje Schloemer, Joachim Wassermann, Wolfgang Friederich, Michael Korn, Thomas Meier, Georg Ruempker, Christine Thomas, Frederik Tilmann, Joachim Ritter
Summary: The German Seismological Broadband Array (DSEBRA) is a network of 100 mobile seismological stations that can operate independently or in conjunction with other stations. The network's first mission was part of the European AlpArray initiative, with the aim of studying seismic activity in the Alps??? Apennines???Carpathians???Dinarides orogenic system. The current deployment of DSEBRA stations covers the Alpine region of Germany, Austria, and Italy, as well as the Pannonian basins of Hungary. Equipped with state-of-the-art technology, these stations provide high-quality real-time seismic data.
SEISMOLOGICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
Philippe Jousset, Gilda Currenti, Benjamin Schwarz, Athena Chalari, Frederik Tilmann, Thomas Reinsch, Luciano Zuccarello, Eugenio Privitera, Charlotte M. Krawczyk
Summary: Understanding physical processes prior to and during volcanic eruptions has improved significantly in recent years, but uncertainties about subsurface structures and undetected processes within the volcano prevent volcanologists from inferring subtle triggering mechanisms of volcanic phenomena. This article demonstrates that distributed acoustic sensing (DAS) with optical fibers allows for remote identification of volcanic events and imaging of hidden near-surface volcanic structural features, providing the basis for improved volcano monitoring and hazard assessment.
NATURE COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
Shanshan Wu, Youqiang Yu, Ting Yang, Mei Xue, Frederik Tilmann, Haopeng Chen
Summary: This study uses seismic data and ambient noise tomography to construct a 3-D crustal shear-wave velocity (Vs) model beneath the Indochina Peninsula. The results show a low-Vs anomaly in the mid-lower crust of the Shan-Thai Block, which may be related to crustal flow from Southeast Tibet. The Khorat Plateau behaves as a rigid block but shows low-Vs anomalies in the lower crust and below the Moho, indicating partial modification by mantle-derived melts. The strike-slip shearing motions of the Red River Fault may dominate crustal deformation at its western flank, where a low-Vs anomaly is observed in the upper-middle crust.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Jannes Muenchmeyer, Ulf Leser, Frederik Tilmann
Summary: The duration of ruptures of the largest earthquakes can range from a few seconds to several minutes. Based on our research, early prediction of earthquake size is difficult, as differentiation between differently sized ruptures only occurs once half of the rupture has been observed. The results suggest a universal initiation behavior for small and large ruptures.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Valerie Maupin, Alexandra Mauerberger, Frederik Tilmann
Summary: The study analyzes the radial anisotropy in the upper mantle of the Fennoscandian Shield using joint inversion of Love and Rayleigh wave phase velocities. Similar radial anisotropy is found in subregions down to at least 200 km depth, with SH waves faster than SV by 2%-3%. Different types of olivine crystallographic preferred orientations (CPOs) are discussed in relation to seismic observations.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Stefan Mroczek, Frederik Tilmann, Jan Pleuger, Xiaohui Yuan, Ben Heit
Summary: To better understand the tectonic structure of the Eastern Alps, a high resolution Moho map was created based on seismic analysis. The map revealed the underthrusting of European crust and a sharp transition to a flat and thinned crust associated with Pannonian extension tectonics. The Adriatic lithosphere also underthrusts northward and becomes steeper towards the Dinarides. The high velocity region in the mantle below the Eastern Alps is likely of European origin.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Peter Makus, Christoph Sens-Schoenfelder, Luc Illien, Thomas R. Walter, Alexander Yates, Frederik Tilmann
Summary: This study analyzes seismic data from the Klyuchevskoy Volcanic Group in Russia to study signals related to volcanic activity. A new technique called time-segmented passive image interferometry is proposed to detect volcanic inflation and deflation. The results show that rainfall and snowfall have the strongest influence on the properties of rocks, and an eruption cycle in 2016 is associated with a significant increase in velocity.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Meteorology & Atmospheric Sciences
H. C. Bloomfield, J. Hillier, A. Griffin, A. L. Kay, L. C. Shaffrey, F. Pianosi, R. James, D. Kumar, A. Champion, P. D. Bates
Summary: This study systematically investigates the correlations between wintertime extremes of wind and flooding, and finds strong positive correlations between wind gusts and precipitation, as well as between wind gusts and river flows at specific timescales. A new flood severity index (FSI) is developed to provide actionable information for insurers and other stakeholders. The study also highlights the potential impact of climate change on severe flood-wind episodes.
WEATHER AND CLIMATE EXTREMES
(2023)
Article
Geography
Joshua J. Thompson, Robert L. Wilby, John K. Hillier, Richenda Connell, Geoffrey R. Saville
Summary: There is growing evidence that physical climate hazards, such as floods and wildfires, have an impact on property prices. This raises concerns about the risks posed to homeowners, insurance and mortgage industries, bank portfolios, and financial systems. Climate gentrification (CG) captures the links between climate hazards, perceptions of risk and resilience, and capital flows in property markets. The study demonstrates how CG has depressed house price growth in flood-exposed locations and discusses ethical concerns and policy implications.
ANNALS OF THE AMERICAN ASSOCIATION OF GEOGRAPHERS
(2023)
Article
Environmental Sciences
Constanza Rodriguez Piceda, Ya-Jian Gao, Mauro Cacace, Magdalena Scheck-Wenderoth, Judith Bott, Manfred Strecker, Frederik Tilmann
Summary: Knowledge of the causative dynamics of earthquakes along subduction-zone interfaces and within oceanic slabs is important for seismic hazard assessments. This study combines seismic tomography, 3D structure analysis, and seismicity to investigate the factors controlling slab seismic activity beneath the southern Central Andes. The hydration state of the lithospheric mantle, oceanic slab, and plate interface can be evaluated using the Vp/Vs ratio. Regions of high Vp/Vs are caused by compaction effects and dehydration reactions, while areas of low Vp/Vs and inferred lower fluid content in the overriding plate are facilitated by enhanced flexural stresses.
COMMUNICATIONS EARTH & ENVIRONMENT
(2023)
Article
Geosciences, Multidisciplinary
Diego Gonzalez-Vidal, Marcos Moreno, Christian Sippl, Juan Carlos Baez, Francisco Ortega-Culaciati, Dietrich Lange, Frederik Tilmann, Anne Socquet, Jan Bolte, Joaquin Hormazabal, Mickael Langlais, Catalina Morales-Yanez, Daniel Melnick, Roberto Benavente, Jannes Muenchmeyer, Rodolfo Araya, Benjamin Heit
Summary: We deployed a dense network in the seismic gap in Chile and obtained a microseismicity catalog of >30,000 events and time series from GNSS stations. We used Bayesian inversion to estimate interplate locking and found two highly locked regions of different sizes controlling seismicity patterns. The region with lower locking coincides with higher seismicity levels and events extending toward the trench.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
Lingyu Zhang, Kristoffer Szilas
Summary: This study presents new petrological and geochemical data for the Narssaq Ultramafic Body (NUB) in the Itsaq Gneiss Complex of SW Greenland. The results indicate that the ultramafic rocks of NUB are not mantle residues, but instead represent crustal cumulates derived from high-Mg magmas.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Rong Xu, Sarah Lambart, Oliver Nebel, Ming Li, Zhongjie Bai, Junbo Zhang, Ganglan Zhang, Jianfeng Gao, Hong Zhong, Yongsheng Liu
Summary: This study investigated the iron isotope compositions of Cenozoic basalts in Southeast China, finding significant variations related to different types of basalts and their respective sources.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
C. J. Ebinger, Miriam C. Reiss, Ian Bastow, Mary M. Karanja
Summary: The East African rift system is formed above mantle upwellings and the formation of rifts is related to lithospheric thinning and magmatic activity. The amount of splitting varies spatially and the fast axes are predominantly parallel to the orientation of the rifts. Thick lithospheric modules have less splitting and different orientations, which may indicate mantle plume flow. Splitting rotates and increases in strength as it enters the rift zones, suggesting that the anisotropy is mainly present at shallow depths.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Correction
Geochemistry & Geophysics
Ekaterina Rojas-Kolomiets, Owen Jensen, Michael Bizimis, Gene Yogodzinski, Lukas Ackerman
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Robert W. Nicklas, Igor S. Puchtel, Ethan F. Baxter
Summary: Oxygen fugacity is a fundamental parameter for understanding redox processes in igneous systems. This study compares the Fe-XANES oxybarometry method with the V-in-olivine method for evaluating fO(2) in MORB lavas. The results show that the V-in-olivine method is not applicable to samples with low MgO content, and that the majority of Archean komatiite sources have lower fO(2) than modern MORB.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Chunfei Chen, Stephen F. Foley, Sebastian Tappe, Huange Ren, Lanping Feng, Yongsheng Liu
Summary: The volatile components CO2 and H2O play a major role in mantle melting and heterogeneity. In this study, Ca isotopes were used to trace the lithological heterogeneity in alkaline magmatic rocks. The results revealed the presence of K-richterite and carbonate components as the source of alkaline magmas with low delta 44/40Ca values. These findings highlight the importance of Ca isotopes as a robust tracer of lithological variation caused by volatiles in the Earth's upper mantle.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Timothee Jautzy, Gilles Rixhon, Regis Braucher, Romain Delunel, Pierre G. Valla, Laurent Schmitt, Aster Team
Summary: Although the current approach to estimate catchment-wide denudation rates using only 10Be concentrations has made significant progress in geomorphology, this study argues for the inclusion of 26Al measurements and testing of steady-state assumptions in slow eroding, formerly glaciated landscapes. The study conducted measurements of both 10Be and 26Al in stream sediments from the Vosges Massif in France and found that elevation, slope, channel steepness, and precipitation were the primary factors controlling denudation rates. The study also revealed a significant relationship between the extent of past glaciation and the cosmogenic (un-)steadiness in the stream sediments.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Erik van der Wiel, Douwe J. J. van Hinsbergen, Cedric Thieulot, Wim Spakman
Summary: Numerical models of Earth's mantle dynamics can predict the vigour and mixing of mantle flow, and the average slab sinking rates are an unexplored parameter that can provide intrinsic information on these characteristics. Through numerical experiments, it has been found that slab sinking rates are strongly correlated with mantle convection and mixing, and may explain geochemical observations from hotspot volcanoes.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)