Article
Geochemistry & Geophysics
John Akoto, Harold Gurrola
Summary: The goal of this study is to investigate the mantle transition zone (TZ) in the Aleutian subduction zone using SdS underside reflections. The results show that the 410 discontinuity is elevated by up to 20 km and the 660 discontinuity is depressed by up to 40 km where the subducting Pacific Plate passes through the TZ. Additionally, the 520 discontinuity (a phase change from wadsleyite to ringwoodite) is observed in regions close to the cold subducting slab in the Aleutian trench.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Jiaqi Li, Min Chen, Jieyuan Ning, Tiezhao Bao, Ross Maguire, Megan P. Flanagan, Tong Zhou
Summary: The study systematically analyzed the trade-off between model parameters in triplication studies using synthetic examples, illustrating the necessity of using array-normalized amplitude. It derived the depths of the 410-km discontinuity and the slab upper surface, revealing that high-frequency waves are required to accurately resolve the detailed structures near the mantle transition zone.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Jiaqi Li, Min Chen, Jieyuan Ning, Tiezhao Bao, Ross Maguire, Megan P. Flanagan, Tong Zhou
Summary: This study analyzed the trade-off between model parameters in triplication studies using synthetic examples and obtained 1-D depth profiles of the wave speed below the Tatar Strait in the Kuril subduction zone. The research also showed the necessity of using high-frequency waves to accurately resolve detailed structures near the mantle transition zone.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Sara L. Dougherty, Chengxin Jiang, Robert W. Clayton, Brandon Schmandt, Steven M. Hansen
Summary: A study in central California reveals a slab-like feature extending from the Pacific coast to the foothills of the Sierra Nevada, connecting the subducted remnant of the Monterey microplate to a high-velocity anomaly in the upper mantle. This anomaly is believed to be a relic of the subduction zone before the capture of the Monterey microplate, rather than delamination of the lithosphere beneath the Sierra Nevada Mountains.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Kai Wang, Yingjie Yang, Chengxin Jiang, Yi Wang, Ping Tong, Tianshi Liu, Qinya Liu
Summary: The study introduces an inversion scheme that alternates between ambient noise surface waves and teleseismic P waves to take advantage of their complementary sensitivities, resulting in a more unified model of the Earth's structure. Both practical field data sets and synthetic tests demonstrate the advantage of alternating inversion over individual inversions in providing detailed information about the Earth's interior structure.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geosciences, Multidisciplinary
Erin Heilman, Thorsten W. Becker
Summary: Mantle plumes can play a significant role in the evolution of Earth and plate tectonics, potentially causing the termination of subduction zones and contributing to the complexity of mantle structures. This effect may be particularly relevant for the early Earth and remain relevant in modern times.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Shaolin Liu, Iman Suardi, Xiwei Xu, Shuxin Yang, Ping Tong
Summary: The establishment of a dense seismic network in Indonesia since 2005 has allowed for high-resolution tomographic images of the subducted Indo-Australian plate beneath Sumatra. The images reveal a generally sinusoidal-shaped slab with varying penetration depths from north to south, as well as a tear at a depth of 120 km possibly linked to the Toba caldera eruption. Additionally, significant variations in the dip of the subducted slab across the Sunda Strait suggest the presence of another subvertical slab tear.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Guanning Pang, Geoffrey A. Abers, Peter E. van Keken
Summary: Seismic wave amplitudes have been sparsely used compared with traveltimes due to their sensitivity to attenuation, scattering, and focusing. However, we have measured and modeled teleseismic body wave amplitudes in the Washington Cascades and found anomalous variations with complex azimuthal dependence. Spectral-element numerical simulations show that the focusing of the wavefield by the Juan de Fuca slab is responsible for some of these anomalies. The amplitudes can be used to refine seismic images and provide information about subducting slab geometry and subduction structure.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Jiayuan Yao, Shaolin Lin, Shengji Wei, Judith Hubbard, Bor-Shouh Huang, Meng Chen, Ping Tong
Summary: By conducting joint inversion of regional and teleseismic P-wave traveltimes, this study reveals a high P-wave velocity anomaly beneath central Myanmar, interpreted as the subducting Indian slab. The dip angle of the slab in the south is larger than that of the slab in the north, suggesting a possible slab tearing phenomenon.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Gerardo Leon Soto, Raul W. Valenzuela, R. Arceo, Eduardo Huesca-Perez, Ricardo Vazquez Rosas
Summary: Shear wave splitting measurements in the Isthmus of Tehuantepec show a predominantly trench-normal pattern of fast polarization orientations, suggesting a corner flow in the mantle wedge and an entrained flow in the subslab region. Fast orientations parallel to the Absolute Plate Motion indicate anisotropy driven by asthenospheric flow in that region. Comparison with measurements in the Mexican subduction zone reveals a 17 degrees clockwise rotation of fast orientations between east and west Mexico, consistent with a 19 degrees clockwise rotation observed in the Middle American Trench.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Leah Langer, Fred F. Pollitz, Jeffrey J. McGuire
Summary: We test a newly developed 2-D elastic reverse time migration (RTM) algorithm based on Helmholtz decomposition for imaging the descending slab in subduction zones using local earthquake sources. The algorithm reconstructs incident and scattered wavefields, isolates P- and S-wave components, and evaluates imaging functions that leverage dominant P and S signals. The method is effective in imaging seismic discontinuities using dense seismic arrays, but limitations arise when using a small aperture array.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
HyeJeong Kim, Hitoshi Kawakatsu, Takeshi Akuhara, Masanao Shinohara, Hajime Shiobara, Hiroko Sugioka, Ryota Takagi
Summary: This study presents reflectivity images of the northeast Japan subduction zone continuous across the ocean and land, overcoming challenges related to noise level and seafloor sediment effects. The use of ocean bottom seismometer data has allowed for better imaging and understanding of the dynamics of the region.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Jingchuan Wang, Yu Jeffrey Gu
Summary: The morphology and composition of subducted slabs in the upper mantle transition zone have direct implications for mantle convection. Investigating the seismic reflectivity structure beneath South America, researchers found broad regions with depressed discontinuities and diminished precursor amplitudes beneath the back-arc region of Nazca subduction. Probabilistic inversion and amplitude-versus-offset inversion techniques were used to determine mantle temperature and composition, showing a mechanically mixed transition zone with basalt enrichment beneath the Amazon basin. This study provides direct evidence for thermochemical anomalies in the mantle and their interactions with subducting slabs.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
John Cornthwaite, Maximiliano J. Bezada, Wenpei Miao, Michael Schmitz, German A. Prieto, Viviana Dionicio, Fenglin Niu, Alan Levander
Summary: The study reveals the subduction structures of the Caribbean plate beneath northwest South America, identifying a detached subducting segment that significantly impacts the uplift of the Merida Andes region. By integrating various datasets, it is concluded that the northern limit of subduction lies south of the Oca-Ancon fault, while the southern limit is located south of the study area.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geochemistry & Geophysics
D. F. Narvaez, P. Samaniego, K. T. Koga, E. F. Rose-Koga, S. Hidalgo, G. Ratzov
Summary: This study investigates the geochemical parameters in continental arc lavas in Ecuador and identifies two types of slab components: aqueous fluids and hydrous siliceous melts. The study also reveals the composition of primitive melts and provides insights into the origins of these components.
Article
Geochemistry & Geophysics
Crelia Padron, Frauke Klingelhoefer, Boris Marcaillou, Jean-Frederic Lebrun, Serge Lallemand, Clement Garrocq, Mireille Laigle, Walter R. Roest, Marie-Odile Beslier, Laure Schenini, David Graindorge, Aurelien Gay, Franck Audemard, Philippe Munch
Summary: The Grenada back-arc basin is located between the Aves Ridge and Lesser Antilles Arc, with varying sedimentary cover thickness and velocity structures in different parts of the basin. The opening of the basin likely proceeded in a direction oblique to the main convergence, with widespread volcanism accompanying the process. More research is needed to explore the direction of opening and the extent of the oceanic-type crust underneath the modern island arc in the southeastern part of the basin.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Clement Garrocq, Serge Lallemand, Boris Marcaillou, Jean-Frederic Lebrun, Crelia Padron, Frauke Klingelhoefer, Mireille Laigle, Philippe Munch, Aurelien Gay, Laure Schenini, Marie-Odile Beslier, Jean-Jacques Cornee, Bernard Mercier de Lepinay, Frederic Quillevere, Marcelle BouDagher-Fadel
Summary: This study refines the understanding of the basement structure, depositional history, tectonic deformation, and vertical motions of the Grenada Basin and its margins by combining a large set of deep-penetrating multichannel seismic reflection data and dredge samples with published data. The study reveals the late Paleocene-early Eocene rifting in a NW-SE direction and subsequent seafloor spreading during the middle Eocene, as well as the subsidence of the Aves Ridge along with the Grenada Basin since at least the middle Eocene. The findings also suggest that bathymetric highs remained shallow enough to develop carbonate platforms until the late Miocene.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
M. Boucard, B. Marcaillou, J-F Lebrun, M. Laurencin, F. Klingelhoefer, M. Laigle, S. Lallemand, L. Schenini, D. Graindorge, J-J Cornee, P. Munch, M. Philippon
Summary: Oblique collision of buoyant provinces against subduction zones often leads to individualizing and rotating regional-scale blocks, while the collision of the Bahamas Bank against the Northeastern Caribbean Plate resulted in forearc fragmentation and formation of small-scale blocks. High-resolution bathymetric and deep seismic data reveal a dramatic tectonic evolution in the Northern Lesser Antilles forearc, with block rotations, forearc fracturing, and V-shaped valleys opening during a past tectonic phase related to margin bending and block rotation.
Article
Geochemistry & Geophysics
Sergio Leon-Rios, Lidong Bie, Hans Agurto-Detzel, Andreas Rietbrock, Audrey Galve, Alexandra Alvarado, Susan Beck, Philippe Charvis, Yvonne Font, Silvana Hidalgo, Mariah Hoskins, Mireille Laigle, Davide Oregioni, Anne Meltzer, Mario Ruiz, Jack Woollam
Summary: This study reveals the underground structures and seismic activity characteristics of central coastal Ecuador using local earthquake tomography, uncovering features of oceanic terranes and the influence of subducted seamounts on earthquakes. These findings play a crucial role in controlling seismic behavior in the region.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Engineering, Geological
Nikos Kalligeris, Vassilios Skanavis, Marinos Charalampakis, Nikolaos S. Melis, Evangelos Voukouvalas, Alessandro Annunziato, Costas E. Synolakis
Summary: On October 30th, 2020, a magnitude 7.0 earthquake off the northern coast of Samos, Greece triggered a tsunami that affected the Greek islands and the Aegean coast of Turkey. Detailed post-event field surveys revealed tsunami height and runup measurements on five islands. The warning message sent by the General Secretariat for Civil Protection of Greece to all cell phones in the eastern Aegean region before the second flood in Vathi highlights the importance of timely evacuation. Inferring complete tsunami hydrographs from measurements of the first two floods in Vathi revealed a rapid rise in water levels of about one meter overland flow depth.
BULLETIN OF EARTHQUAKE ENGINEERING
(2022)
Article
Geochemistry & Geophysics
Nikos Kalligeris, Vassilios Skanavis, Nikolaos S. Melis, Emile A. Okal, Aggeliki Dimitroulia, Marinos Charalampakis, Patrick J. Lynett, Costas E. Synolakis
Summary: This article studies the earthquake and tsunami event that occurred in Crete, Greece in 2020. Through analysis of seismic records and field observations, it reveals the mechanism of tsunami generation and its impacts on coastal areas. The results indicate that using scaling laws to infer seafloor deformations is appropriate, and shallow-water equations can be used to simulate most tsunami events. It also highlights the lack of awareness of tsunami hazards among people.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Andrey Babeyko, Stefano Lorito, Francisco Hernandez, Joern Lauterjungl, Finn Lovholt, Alexander Rudloff, Mathilde Sorensen, Alexey Androsov, Inigo Aniel-Quiroga, Alberto Armigliato, Maria Ana Baptista, Enrico Baglione, Roberto Basili, Joern Behrens, Beatriz Brizuela, Sergio Brunie, M. Didem Cambaz, Juan Cantavella-Nadal, Fernando Carrilho, Ian Chandler, Denis Chang-Seng, Marinos Charalampakis, Lorenzo Cugliari, Clea Denamiel, Gozde Guney Dogan, Gaetano Festa, David Fuhrman, Alice-Agnes Gabriel, Pauline Galea, Steven J. Gibbons, Mauricio Gonzalez, Laura Graziani, Marc-Andre Gutscher, Sven Harig, Helen Hebert, Constantin Ionescu, Fatemeh Jalayer, Nikos Kalligeris, Utku Kanoglu, Piero Lanucara, Jorge Macias Sanchez, Shane Murphy, Ocal Necmioglu, Rachid Omira, Gerassimos A. Papadopoulos, Raphael Paris, Fabrizio Romano, Tiziana Rossetto, Jacopo Selva, Antonio Scala, Roberto Tonini, Konstantinos Trevlopoulos, Ioanna Triantafyllou, Roger Urgeles, Roberto Vallone, Ivica Vilibic, Manuela Volpe, Ahmet C. Yalciner
Summary: The European tsunami community has attained the status of Candidate Thematic Core Service (cTCS) within the European Plate Observing System (EPOS), providing support and a platform for tsunami research and risk management. The cTCS will address the needs in tsunami science and risk mitigation through four thematic pillars.
ANNALS OF GEOPHYSICS
(2022)
Article
Multidisciplinary Sciences
J. Diaz, I DeFelipe, M. Ruiz, J. Andres, P. Ayarza, R. Carbonell
Summary: The analysis of background noise in seismic networks is a powerful tool for studying crustal structure and monitoring natural and human-induced processes. This study demonstrates the usefulness of data from controlled source experiments, especially with high-density deployments, in monitoring such processes. Using wide-angle reflection and refraction seismic profile data in the central-northwest part of Iberia, various signals related to aircrafts, road traffic, quarry blasts, wind blow, rainfall, and thunder are identified. Notably, signals generated by a helicopter and an airplane flying parallel to the profile are observed along a 200 km distance with a spatial resolution of 350 m, providing exceptional dataset.
SCIENTIFIC REPORTS
(2022)
Article
Geochemistry & Geophysics
K. Ezenwaka, B. Marcaillou, M. Laigle, F. Klingelhoefer, J. -F. Lebrun, M. Paulatto, Y. Biari, F. Rolandone, F. Lucazeau, A. Heuret, T. Pichot, H. Bouquerel
Summary: The fluid circulation and elevated pore pressure play a crucial role in controlling the seismogenic behavior along the plate interface in the Lesser Antilles subduction zone. Heat-flow variations indicate different fluid circulation patterns, which are closely related to the location of seismic activity.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Lili Feng, Jordi Diaz
Summary: A high-resolution azimuthally anisotropic Vs model beneath the westernmost Mediterranean is constructed based on Rayleigh wave dispersions obtained from seismic stations. The model reveals consistent anisotropy with the analysis of SKS splitting, vertically coherent mantle deformation, and complex anisotropy in the Alboran Basin related to mantle flow pattern.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Multidisciplinary Sciences
J. Diaz, M. Ruiz, M. Udina, F. Polls, D. Marti, J. Bech
Summary: Data from a dense seismic network in the Cerdanya basin is used to track meteorological events. Seismic data can be used as a proxy for rainfall, with the seismic amplitude following a similar evolution to radar reflectivity values. Seismic data complements rain-gauge and weather radar observations to describe rainfall fields at high resolution.
SCIENTIFIC REPORTS
(2023)
Article
Geochemistry & Geophysics
Matthieu Sylvander, Sebastien Chevrot, Jean-Baptiste Ammirati, Sylvain Calassou, Magali Collin, Jordi Diaz, Nikos Martakis, Katerina Polychronopoulou, Antonio Villasenor
Summary: An unusual seismic sequence was recorded during a passive seismic experiment in the foreland of the western Pyrenees in southwest France. The sequence consisted of more than 600 events clustered in a small volume, suggesting a connection with hydrogen leaks on the surface.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2023)
Article
Geochemistry & Geophysics
Jordi Diaz, Sergi Ventosa, Martin Schimmel, Mario Ruiz, Albert Macau, Anna Gabas, David Marti, Ozgenc Akin, Jaume Verges
Summary: In this study, ambient seismic noise acquired in the Cerdanya Basin was used to evaluate the capability of different methodologies to map the geometry of a small-scale sedimentary basin. The results from various techniques, including autocorrelations, ambient noise Rayleigh wave tomography, HVSR, and band-pass-filtered ambient noise amplitude mapping, consistently showed that the deeper part of the basin is located in its central part, reaching depths of 600-700 m close to the Tet fault trace. The overall consistency between the results provides solid constraints to the basement depth estimation and helps improve the geological characterization of the Cerdanya Basin.
Article
Environmental Sciences
Jordi Diaz
Summary: According to global seismic observations, the 2022 eruption of the Hunga-Tonga volcano stimulated a low-frequency and long-lasting coupling between the atmosphere and the solid Earth, likely resulting from the excitation of Earth's normal modes. The eruption started around 04:00 and lasted for 3.5 days, during which atmospheric waves circled the Earth more than two times and were detected seismically. Additionally, very low frequency signals were detected for several hours, interpreted as the excitation of Earth normal modes.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Review
Geosciences, Multidisciplinary
Sebastien Chevrot, Matthieu Sylvander, Antonio Villasenor, Jordi Diaz, Laurent Stehly, Pierre Boue, Vadim Monteiller, Roland Martin, Maximilien Lehujeur, Stephen Beller, Jacques Brives, Adnand Bitri, Sylvain Calassou, Magali Collin, Mary Ford, Laurent Jolivet, Gianreto Manatschal, Emmanuel Masini, Frederic Mouthereau, Olivier Vidal
Summary: This contribution reviews the challenges of imaging collisional orogens using the example of the Pyrenees. New tomographic images provide evidence for continental subduction in the western and central Pyrenees, but not in the eastern Pyrenees. Relics of a Cretaceous hyper-extended and segmented rift are found within the North Pyrenean Zone.
BSGF-EARTH SCIENCES BULLETIN
(2022)
