News Item
Geosciences, Multidisciplinary
Ryo Okuwaki
Summary: A global investigation has found that faults rupturing faster than seismic waves can travel is more common and destructive than previously believed.
Article
Multidisciplinary Sciences
Jerome Lave, Cyrielle Guerin, Pierre G. Valla, Valery Guillou, Thomas Rigaudier, Lucilla Benedetti, Christian France-Lanord, Ananta Prasad Gajurel, Guillaume Morin, Jean Pascal Dumoulin, Christophe Moreau, Valier Galy
Summary: Despite numerous studies, the erosion mechanisms of the very high Himalayan peaks remained unknown. However, geological evidence suggests that mega-rockslides could be a mode of high-altitude erosion, preventing disproportionate growth of the peaks. These rockslides also have implications for landscape evolution and natural hazards.
Editorial Material
Geochemistry & Geophysics
Ze'ev Reches, Jay Fineberg
Summary: Earthquakes are caused by dynamic fractures due to overstresses, not governed by the frictional properties of faults. Frictional interfaces can sustain a wide range of stresses before sliding, generating stress-fields and rupture dynamics. The values of stresses and energy dissipation are determined by fault frictional properties.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geosciences, Multidisciplinary
Xin Cui, Zefeng Li, Yan Hu
Summary: According to machine learning classification of moderate to large earthquakes, the differences between deep and shallow earthquakes can be explained by Earth's depth-dependent rigidity instead of different rupture processes.
Article
Geosciences, Multidisciplinary
Eric O. Lindsey, Rishav Mallick, Judith A. Hubbard, Kyle E. Bradley, Rafael V. Almeida, James D. P. Moore, Roland Burgmann, Emma M. Hill
Summary: The study introduces a new method to infer the slip rate deficit of offshore megathrusts, providing better understanding of seismic slip behavior. It reveals that the shallow fault generally has a slip rate deficit between 80% and 100% of the plate convergence rate when locked patches are present. This finding suggests a potentially higher global tsunami hazard than currently recognized.
Article
Geochemistry & Geophysics
Dara E. Goldberg, Kirstie L. Haynie
Summary: Global Navigation Satellite Systems (GNSSs) have advanced significantly in the past few decades, providing a dataset that surpasses its original intended purposes. High-rate GNSS receivers now allow for routine consideration of dynamic earthquake ground motions with centimeter-level accuracy. Real-time GNSS observations have lower accuracy compared to post-processed data, but when used in conjunction with available seismic data sources, they are sufficient for rapid earthquake characterization.
SEISMOLOGICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Amir Salaree, Yihe Huang, Marlon D. Ramos, Seth Stein
Summary: Studies show that tsunamis from earthquakes of various magnitudes have affected the Cascadia region in the past. Simulations suggest that earthquakes with a magnitude of Mw >= 8.5 occurring in the middle segments of the subduction zone could generate coastal tsunami amplitudes comparable to the largest expected event. Results from rupture and tsunami simulations indicate that the concave coastline geometry of the Pacific Northwest coast focuses tsunami energy between latitudes 44 degrees and 45 degrees in Oregon.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Multidisciplinary Sciences
Anna Pomyalov, Fabian Barras, Thibault Roch, Efim A. Brener, Eran Bouchbinder
Summary: This article presents a theoretical study on slip pulses in realistic rate- and state-dependent frictional systems. The research shows that slip pulses are inherently unstable objects, but their dynamical evolution is closely linked to their stable counterparts. The study also reveals that slip pulses exist on a steady-state line and their non-steady dynamics are controlled by a single slow unstable mode. This theoretical picture is supported by large-scale simulations.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Geochemistry & Geophysics
KeLin Wang
Summary: Research has shown that subduction megathrusts are extremely weak, with effective coefficients of friction usually around 0.03, explaining why subduction zones do not form orogenic belts. The weakest megathrusts that produce large earthquakes do not require strong faults or high stress, only geological conditions that facilitate seismic rupture propagation and expansion. These results imply that stress drop in great earthquakes is not negligible compared to the faults' strength, and the geological reasons for their weakness are not yet clear, possibly due to high pore fluid pressure or the presence of weak hydrous minerals in fault gouge.
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
(2021)
Article
Geosciences, Multidisciplinary
Dawei Gao, Honn Kao, Bei Wang
Summary: This study investigates the validity of using cross-correlation coefficient (CC) as a proxy for repeater identification in both synthetic and real earthquake experiments. It reveals that CC is influenced by various factors and lacks resolution in identifying true repeaters, proposing a new criterion for reliable repeater identification. These results suggest the importance of systematically rechecking previously identified repeaters and associated interpretations/hypotheses.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Franciscus M. Aben, Nicolas Brantut
Summary: The study demonstrates that the dilation effect in rock fracture experiments can stabilize dynamic fault slip, while changes in pore fluid pressure can affect the stability of fault slip. The observations can be quantitatively explained by using a spring-slider model.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Zachary D. Smith, W. Ashley Griffith
Summary: This study investigates the development of off-fault damage through successive tensile loading. The results show that fracture density increases during each earthquake cycle, and pulverized rock can be produced at low strain rates.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Jiafeng Li, Kejie Chen, Haishan Chai, Guoguang Wei
Summary: This paper assesses tsunami potential by analyzing co-seismic ionospheric disturbances (CIDs), and finds that there are no deterministic scaling relations between earthquake size and tsunami potential. The study shows that CIDs generated by two Chilean events are stronger than those generated by the Alaska event, despite similar earthquake magnitudes. The analysis of CIDs from the Alaska earthquake reveals less seafloor uplift and hazardous flooding.
Article
Geochemistry & Geophysics
Suli Yao, Hongfeng Yang
Summary: This study examines the ground motion predictions in locking-based dynamic rupture scenarios by comparing them with ground motion models (GMMs) and observations in a real earthquake. The results show that the predictions from locking models are generally consistent with GMMs, but differ in spatial patterns due to the rupture directivity effect. The study emphasizes the importance of considering rupture dynamics and stress heterogeneities in earthquake source characterization and highlights the potential application of locking models in seismic hazard assessment.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Chao Liang, Jean-Paul Ampuero, Daniel Pino Munoz
Summary: This study investigates for the first time the prevalence of supershear ruptures across multiple earthquake cycles on long faults, finding that supershear events only occur in a specific range of friction parameters that are not commonly observed in laboratory experiments, which may explain the rarity of supershear earthquakes.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
Andrea Licciardi, Quentin Bletery, Bertrand Rouet-Leduc, Jean-Paul Ampuero, Kevin Juhel
Summary: This study develops a deep learning model that utilizes speed-of-light prompt elastogravity signals (PEGS) to track earthquake growth in real time. The algorithm is shown to be able to instantaneously track an earthquake source time function on real data. This research has the potential to be transformative for tsunami early warning.
Article
Multidisciplinary Sciences
E. Calais, S. Symithe, T. Monfret, B. Delouis, A. Lomax, F. Courboulex, J. P. Ampuero, P. E. Lara, Q. Bletery, J. Cheze, F. Peix, A. Deschamps, B. de Lepinay, B. Raimbault, R. Jolivet, S. Paul, S. St Fleur, D. Boisson, Y. Fukushima, Z. Duputel, L. Xu, L. Meng
Summary: On August 14, 2021, a 7.2 magnitude Nippes earthquake occurred in Haiti within the same fault zone as the devastating 7.0 magnitude earthquake in 2010. However, field access was limited during the event and conventional seismometers were inoperative. Citizen seismometers installed in 2019 provided critical near-field data to quickly understand the mainshock mechanism and monitor aftershocks. Machine learning applied to data from the closest citizen seismometer allowed accurate forecasting of aftershocks, demonstrating the utility of citizen science in understanding major earthquakes.
Article
Geochemistry & Geophysics
Philippe Danre, Louis De Barros, Frederic Cappa
Summary: Many studies have found a correlation between seismic moment and injected fluid volume in fluid injection-induced earthquake sequences, but this correlation becomes uncertain when looking at individual events. In this study, the authors use the similarity between natural and injection-induced swarms to develop new methods for estimating fluid volume, shedding light on the fluid dynamics that trigger natural swarms.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geosciences, Multidisciplinary
Han Zhang, Margaret Glasgow, Brandon Schmandt, Weston A. Thelen, Seth C. Moran, Amanda M. Thomas
Summary: Estimating the hypocenter depth improves our understanding of active volcanoes and shows changing seismicity distribution before and after eruptions. This study focuses on Mount St. Helens, the most active volcano in the Cascades Range, and evaluates the accuracy of hypocenters before and after the 2004-2008 eruption using new resources. The results indicate a concentration of seismicity between sea level and approximately 1 km above it, suggesting a re-equilibration of the shallow magmatic system after the dome-building eruption.
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
(2022)
Article
Geochemistry & Geophysics
Caroline Chalumeau, Hans Agurto-Detzel, Louis De Barros, Philippe Charvis
Summary: By analyzing the source properties of 1514 aftershocks of the 2016 Pedernales earthquake in Ecuador, we are able to determine accurate seismic moments, stress drops, and P and S corner frequencies. We find that stress drops appear to increase with seismic moment and depend on their distance to the trench. The temporal evolution of source properties is examined through repeating earthquakes, revealing that variations within families are spatially variable, except near the trench where stress drops systematically decrease over time, indicating an increase in pore fluid pressure.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Louis De Barros, Yves Guglielmi, Frederic Cappa, Christophe Nussbaum, Jens Birkholzer
Summary: Fault slip induced by fluid perturbation in shale formations can impact the integrity of shale caprocks for reservoirs holding buoyant fluids, and a better understanding of these processes is critical for reservoir monitoring. In this study, seismic responses of a shale fault exposed to fluid pressurization during an injection experiment were analyzed. Two types of seismic signals were observed: tremors associated with fluid-induced slip propagation, and micro-earthquakes triggered by stress perturbations. Tremors serve as a more direct observation for fluid-induced slip, providing a useful tool for monitoring fluid leakage and sealing integrity.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Alister Trabattoni, Francesco Biagioli, Claudio Strumia, Martijn van den Ende, Francesco Scotto di Uccio, Gaetano Festa, Diane Rivet, Anthony Sladen, Jean Paul Ampuero, Jean-Philippe Metaxian, Eleonore Stutzmann
Summary: Distributed acoustic sensing (DAS) has become a well-established technology in seismology, but its strain data cannot be readily applied to conventional seismological tools. This study proposes a strategy based on deformation to convert strain rate measurements to particle motion, and demonstrates its effectiveness through theoretical analysis and real data comparisons.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Marion Baques, Louis De Barros, Maxime Godano, Clara Duverger, Herve Jomard
Summary: The Ubaye Region in the French Western Alps is one of the most seismically active regions in France, experiencing mainshock-aftershock sequences, seismic swarms, and complex sequences. In this study, a regional catalogue of existing focal mechanisms is compiled, and 100 new calculated focal mechanisms of aftershocks following a mainshock in 2014 are added. The results suggest that fluid pressure is a common triggering mechanism for the seismic activity in the region.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Anna Serpetsidaki, Vasilis Kapetanidis, Panagiotis Elias, Alexis Rigo, Ioannis Spingos, Louis De Barros, Olivier Lengline, Simon Bufferal, Andreas Karakonstantis, Pascal Bernard, Pierre Briole, Jiri Zahradnik, George Kaviris, Vladimir Plicka, Efthimios Sokos, Nicholas Voulgaris
Summary: The seismic sequence in the Western Gulf of Corinth, Greece from 2020 to 2021 has been analyzed using seismological and geodetic data. The study reveals that the sequence involved seismic migration and triggering by pore-pressure diffusion due to fluid intrusion. The analysis of focal mechanisms and fault plane modeling provide insights into the faulting characteristics.
Article
Multidisciplinary Sciences
Julian David Pelaez Quinones, Anthony Sladen, Aurelien Ponte, Itzhak Lior, Jean-Paul Ampuero, Diane Rivet, Samuel Meule, Frederic Bouchette, Ivane Pairaud, Paschal Coyle
Summary: Distributed Acoustic Sensing (DAS) technology can convert seafloor fiber-optic telecommunication cables into temperature anomaly sensors, allowing for high-resolution monitoring of oceanic processes. The study demonstrates the potential of DAS in observing internal waves and upwelling, providing a broader understanding of seafloor temperature fluctuations.
SCIENTIFIC REPORTS
(2023)
Article
Computer Science, Artificial Intelligence
Martijn van den Ende, Itzhak Lior, Jean-Paul Ampuero, Anthony Sladen, Andre Ferrari, Cedric Richard
Summary: Fiber-optic distributed acoustic sensing (DAS) is a versatile technology for vibration measurements with applications in various seismic signal analysis. It can turn fiber-optic cables into seismic arrays, enabling measurements in inaccessible environments. However, handling different types of noise in these new environments poses challenges for traditional data analysis workflows. In this work, we propose a deep learning approach to remove spatially incoherent noise without any assumptions and demonstrate its excellent performance on synthetic and real-world DAS data.
IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS
(2023)
Article
Geochemistry & Geophysics
Pablo Lara, Quentin Bletery, Jean-Paul Ampuero, Adolfo Inza, Hernando Tavera
Summary: Ensemble Earthquake Early Warning System (E3WS) is a system that utilizes Machine Learning algorithms to detect, locate, and estimate the magnitude of earthquakes using P-wave recordings from a single station. With high accuracy and agility, the system provides timely earthquake alerts, allowing for potential protective actions.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Edhah Munaibari, Lucie Rolland, Anthony Sladen, Bertrand Delouis
Summary: By using GNSS data to monitor TEC, it is possible to detect ionospheric disturbances caused by tsunami-induced internal gravity waves. Even in near-field regions, regular tsunamis can be distinguished from initial air-sea waves through GNSS-TEC measurements.
PURE AND APPLIED GEOPHYSICS
(2023)
Proceedings Paper
Computer Science, Artificial Intelligence
Yacine Khacef, Martijn van den Ende, Andre Ferrari, Cedric Richard, Anthony Sladen
Summary: Distributed Acoustic Sensing (DAS) technology can record vibrations on fiber optic cables, including those generated by vehicular traffic. This study proposes a Machine Learning (ML) model that estimates vehicle speed using DAS data. The model utilizes Continuous Piecewise Affine (CPA) transformations to extract the speed as a function of space and time, demonstrating faster estimation compared to non-ML solutions.
2022 56TH ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS, AND COMPUTERS
(2022)
Article
Geosciences, Multidisciplinary
Malgorzata Chmiel, Maxime Godano, Marco Piantini, Pierre Brigode, Florent Gimbert, Maarten Bakker, Francoise Courboulex, Jean-Paul Ampuero, Diane Rivet, Anthony Sladen, David Ambrois, Margot Chapuis
Summary: This study demonstrates the impact of Storm Alex on surface and deep-layer processes, and highlights the use of seismological observations to gain insights into rainfall-runoff dynamics during floods.
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES
(2022)
