Article
Geochemistry & Geophysics
Yujiang Xie, Catherine A. Rychert, Nicholas Harmon
Summary: The elastic and anelastic structures of the Earth provide fundamental constraints for understanding its physical and chemical properties. Deciphering small variations in seismic wave velocity and amplitude can be challenging, but advanced techniques such as full-waveform inversion can be useful.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
S. Adourian, C. Lyu, Y. Masson, F. Munch, B. Romanowicz
Summary: In this study, we propose a general framework called 'box tomography' that couples different numerical seismic wave propagation solvers. This approach aims to reduce the computational cost of full-waveform inversion for structures within a target region when sources and receivers are located far from the region. We extend the implementation of this approach to a 3-D global elastic earth model, where both sources and stations are outside the target region. We demonstrate the efficiency and versatility of this approach through benchmark tests and believe it has great potential for imaging remote target regions in the deep mantle.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Quan Zhang, Yunfeng Chen, Fangxue Zhang, Yangkang Chen
Summary: This study proposes a method that improves the conventional RF imaging workflow by introducing high-resolution Radon transform (RT) to data pre-processing. It effectively reduces noise and improves the coherence of converted phases. Experimental results show that this method achieves good performance in subsurface imaging.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Tsutomu Takahashi, Yuka Kaiho, Yasushi Ishihara, Koichiro Obana, Seiichi Miura, Shuichi Kodaira, Yoshiyuki Kaneda
Summary: This study introduces a trans-dimensional approach for the 3-D imaging of random inhomogeneity using the reversible jump Markov chain Monte Carlo (rjMCMC) method, and analysis of seismic data at the southern Ryukyu arc in southwest Japan revealed anomalies with strong and weak inhomogeneities.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Marta Pienkowska, Vadim Monteiller, Tarje Nissen-Meyer
Summary: This paper presents a new method for studying wave propagation that can decipher small structures inside the Earth at high resolution. The method combines a global Green's functions database with a local 3-D model, offering flexibility and the ability to couple 3-D wavefields, suitable for wave propagation applications in various fields.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Y. Lu, Y. Ben-Zion
Summary: Crustal seismic velocity models are essential for various applications in seismology. In this study, a systematic workflow is presented to assess the accuracy of velocity models using full-waveform simulations. The performance of four regional seismic velocity models for southern California is evaluated, and it is found that the model CVM-S4.26.M01 performs the best overall. However, discrepancies are observed in basin structures and around large fault zones.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Kees Wapenaar, Marcin Dukalski, Christian Reinicke, Roel Snieder
Summary: Many seismic imaging methods use wavefield extrapolation operators to redatum sources and receivers from the surface into the subsurface. We discuss wavefield extrapolation operators that account for internal multiple reflections, including propagator matrices, transfer matrices, and Marchenko focusing functions. These operators allow for accurate wavefield propagation and focusing in heterogeneous media, avoiding common approximations used in previous methods. Understanding the relationships between these operators can lead to new developments in Marchenko theory and improve applications in wavefield focusing, Green's function retrieval and imaging.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Xu Liu
Summary: Correctly selecting the vertical slowness is crucial for obtaining physically acceptable reflection/transmission coefficients for inhomogeneous plane waves in dissipative media. The continuity criterion and elastic consistence are ensured through the branch-cut theory and definition of mixed principal values. This research provides a method to obtain continuous and elastically consistent viscoelastic R/T coefficients, with a focus on the importance of continuity and consistency in the process.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Carl Martin, Thomas Bodin, Sanne Cottaar
Summary: This study targets ultra-low velocity zones (ULVZs) on the core-mantle boundary (CMB) using the postcursors of S core-diffracted phases (Sdiff) caused by ULVZs. It employs a reversible-jump Markov chain Monte Carlo inversion setup to generate probabilistic maps based on the traveltimes of these postcursors. The study extends 2-D wave front tracking (2DWT) software to model the full multipathing behavior of Sdiff postcursors and compute arrival times for ULVZ input velocity structures. The results demonstrate the ability to accurately recover ULVZ size and velocity reduction and reveal the trade-off between these parameters around the edge of the ULVZ.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Xu Liu, Huijian Li, Abdullatif A. Al-Shuhail, Bo Liu, Zhengyong Ren
Summary: Research has investigated the complexities of seismic reflection/transmission problems in various porous materials described by poro-viscoelastic theories. It has been shown that even simple plane waves at plane interfaces between different isotropic viscoelastic solids are more complicated than initially expected. Further study is needed to address the difficulties in accurately selecting the signs of vertical slowness vectors in order to calculate R/T coefficients without unphysical discontinuity.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Xu Liu, Stewart Greenhalgh, Manjeet Kumar, Huijian Li, Bo Liu, Qinzhuo Liao, Xingguo Huang
Summary: In this paper, the reflection and transmission coefficients of spherical waves at a plane interface separating two dissimilar viscoelastic solids are rigorously investigated. It is shown that selecting the correct vertical slowness can be circumvented by using the Sommerfeld integral appropriate for the dissipative materials. However, the resulting phase curves of the complex spherical wave R/T coefficients may be of opposite sign to the corresponding phase curves of plane waves due to the non-uniqueness of the latter for post-critical wave incidence.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Carl Martin, Thomas Bodin, Sanne Cottaar
Summary: This study presents a new dataset containing nearly 100 earthquakes, providing clear evidence of the Hawaiian ultra-low velocity zone (ULVZ) in the S core-diffracted phase (Sdiff). Using a Bayesian inversion approach, the researchers characterized the 2-D morphology and velocity of the Hawaiian ULVZ, revealing that it is smaller in size than previously estimated and has an elliptical shape, oriented along the direction of the large low-shear velocity province boundary.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Christoph Sens-Schoenfelder, Ebru Bozdag, Roel Snieder
Summary: The rotation of the Earth affects the propagation of seismic waves, as the Coriolis force leads to global coupling between spheroidal and toroidal wave modes. Through wavefield simulations, it is shown that the Coriolis force can cause coupling and conversion between surface wave types depending on various factors. Resonant coupling gradually converts energy between different wave types, with location-dependent efficiency driven by equal phase velocities at specific periods.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
S. Rost, G. A. Houseman, A. W. Frederiksen, D. G. Cornwell, M. Kahraman, S. Altuncu Poyraz, U. M. Teoman, D. A. Thompson, N. Turkelli, L. Gulen, M. Utkucu, T. J. Wright
Summary: Research using dense seismic data reveals the subsurface structure of the North Anatolian Fault Zone, with findings showing lateral incoherence of crustal interfaces, contrasting crustal structures on either side of the fault zone, and strong variations in structure both north-south and east-west within the study region. The results suggest the presence of major shear zones throughout the crust and into the lithospheric mantle beneath the fault zone, indicating a strong coupling of strain at these depths.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Andreas Fichtner, Adonis Bogris, Daniel Bowden, Konstantinos Lentas, Nikolaos S. Melis, Thomas Nikas, Christos Simos, Iraklis Simos, Krystyna Smolinski
Summary: Transmission-based fibre-optic sensing offers a distributed measurement alternative to scattering-based techniques. This study develops a formalism to calculate sensitivity kernels of transmitted optical phase changes, proving that optical phase delays can effectively provide distributed measurements when analyzed in different time windows.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Lucia Gualtieri, Etienne Bachmann, Frederik J. Simons, Jeroen Tromp
Summary: Secondary microseisms are ambient noise vibrations caused by ocean activity and dominate seismic records worldwide at periods between 3 and 10 seconds. Using a spectral-element method for global-scale modeling, Love waves naturally emerge due to seismic wavefield interaction with Earth heterogeneity, particularly in the mantle. The distribution of surface sources, topography, and bathymetry are crucial for understanding the generation and propagation of Love waves in secondary microseisms.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Peter Danecek, Stefano Pintore, Salvatore Mazza, Alfonso Mandiello, Massimo Fares, Ivano Carluccio, Emiliano Della Bina, Diego Franceschi, Milena Moretti, Valentino Lauciani, Matteo Quintiliani, Alberto Michelini
Summary: The Istituto Nazionale di Geofisica e Vulcanologia is a founding partner of the EIDA federation, managing the EIDA data distribution node in Italy. Their data archive currently contains 90 TBytes of waveform data available for download, originating from various networks and stations mainly in Italy and the Mediterranean region, with an annual growth rate of 11 TB.
SEISMOLOGICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
Samarth G. Kashyap, Srijan Bharati Das, Shravan M. Hanasoge, Martin F. Woodard, Jeroen Tromp
Summary: Normal-mode helioseismic data analysis uses observed solar oscillation spectra to infer perturbations in the solar interior due to global and local-scale flows and structural asphericity. Differential rotation is the dominant global-scale axisymmetric perturbation, primarily constrained using measurements of frequency splittings via a-coefficients. However, analyzing eigenfunction corrections that respect cross-coupling of modes across multiplets provides a more accurate approach, although it results in a wider spread of a-coefficients compared to frequency splittings. The study demonstrates the effectiveness of Bayesian statistics in inferring a-coefficients due to differential rotation from cross-spectra for modes with angular degrees l = 50-291, with the inferred values close to frequency-splitting values for l > 200 but failing for l < 50 due to insensitivity of the measurement. The results highlight mode-coupling as an important helioseismic technique for inferring internal solar structure and dynamics.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2021)
Article
Geochemistry & Geophysics
Yanadet Sripanich, Ivan Vasconcelos, Jeroen Tromp, Jeannot Trampert
Summary: This study emphasizes the importance of considering different definitions of stress and their effects on seismic quantities in seismic wave propagation. By revisiting the fundamental theoretical foundation, the study investigates the connection between stress and variations in elastic moduli, using both traditional elasticity tensor and adiabatic pressure derivatives. Additionally, the study explores the connection with micromechanical structures and their practical applications.
Article
Geochemistry & Geophysics
Lucia Margheriti, Concetta Nostro, Ornella Cocina, Mario Castellano, Milena Moretti, Valentino Lauciani, Matteo Quintiliani, Andrea Bono, Francesco Mariano Mele, Stefano Pintore, Placido Montalto, Rosario Peluso, Giovanni Scarpato, Sandro Rao, Salvatore Alparone, Sergio Di Prima, Massimo Orazi, Antonio Piersanti, Gianpaolo Cecere, Marco Cattaneo, Annamaria Vicari, Vincenzo Sepe, Christian Bignami, Luisa Valoroso, Marco Aliotta, Adriano Azzarone, Paola Baccheschi, Aldo Benincasa, Fabrizio Bernardi, Ivano Carluccio, Emanuele Casarotti, Carmelo Cassisi, Barbara Castello, Francesca Cirilli, Marcello D'Agostino, Ciriaco D'Ambrosio, Peter Danecek, Walter De Cesare, Emiliano Della Bina, Alessandro Di Filippo, Raffaele Di Stefano, Licia Faenza, Luigi Falco, Massimo Fares, Pietro Ficeli, Diana Latorre, Maria Concetta Lorenzino, Alfonso Mandiello, Alessandro Marchetti, Salvatore Mazza, Alberto Michelini, Anna Nardi, Marina Pastori, Maurizio Pignone, Michele Prestifilippo, Patrizia Ricciolino, Gianpaolo Sensale, Laura Scognamiglio, Giulio Selvaggi, Orazio Torrisi, Francesco Zanolin, Alessandro Amato, Francesca Bianco, Stefano Branca, Eugenio Privitera, Salvatore Stramondo
Summary: The Istituto Nazionale di Geofisica e Vulcanologia (INGV) is an Italian research institution specializing in earth sciences, focusing on seismic, volcanic, and tsunami risk monitoring. It operates the Italian National Seismic Network and is involved in earthquake detection and tsunami warning services. The institute aims to provide earthquake information and improve volcanic surveillance through various networks and data systems.
SEISMOLOGICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Angelo Strollo, Didem Cambaz, John Clinton, Peter Danecek, Christos P. Evangelidis, Alexandru Marmureanu, Lars Ottemoller, Helle Pedersen, Reinoud Sleeman, Klaus Stammler, Daniel Armbruster, Jarek Bienkowski, Kostas Boukouras, Peter L. Evans, Massimo Fares, Cristian Neagoe, Stefan Heimers, Andres Heinloo, Matthias Hoffmann, Philippe Kaestli, Valentino Lauciani, Jan Michalek, Erich Odon Muhire, Mehmet Ozer, Lucian Palangeanu, Constanza Pardo, Javier Quinteros, Matteo Quintiliani, Jose Antonio Jara-Salvador, Jonathan Schaeffer, Antje Schloemer, Nikolaos Triantafyllis
Summary: The European Integrated Data Archive (EIDA) is an infrastructure that provides access to seismic-waveform archives collected by European agencies. It currently offers seamless access to seismic data from 12 data archives with a growing user base and data holdings. EIDA is actively developing new approaches to data management for emerging technologies and challenges to meet evolving demands.
SEISMOLOGICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Qiancheng Liu, Stephen Beller, Wenjie Lei, Daniel Peter, Jeroen Tromp
Summary: In this study, the BFGS algorithm was modified to perform uncertainty quantification for large-scale applications, with the combination of random singular value decomposition for a low-rank approximation of the inverse Hessian. Different initial, diagonal Hessian matrices were used as pre-conditioners in elastic FWI applications to compare performance.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Lucas Sawade, Stephen Beller, Wenjie Lei, Jeroen Tromp
Summary: The global centroid-moment tensor (GCMT) project has determined earthquake location and source parameters using a 1-D reference earth model. However, a new methodology using a 3-D earth model has revealed biases in the standard approach. This paper presents a revised catalogue of centroid-moment tensors (CMT) computed using a 3-D model, which shows significant differences from the GCMT catalogue.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Leah Langer, Stephen Beller, Evan Hirakawa, Jeroen Tromp
Summary: Earthquakes often occur in regions with complex material structure, but most co-seismic modeling studies use simplified, homogeneous elastic structures, which may introduce bias into estimated slip models. This study investigates the impact of 3-D elastic structure on forward models of co-seismic surface deformation using a synthetic model of a sedimentary basin.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geosciences, Multidisciplinary
Daniel Stich, Josue Casado Rabasco, Jose Maria Madiedo, Juan Luis Guerrero Rascado, Jose Morales Soto
Summary: A meteor event in southern Spain on 11 December 2016 was accompanied by an audible boom and vibrations. By analyzing the near-field pressure wave recorded by 44 local seismic stations, it was found that the seismic detections can be attributed to a point source at a height of 38 km, which coincides with the most luminous fragmentation event captured by meteor cameras. The study also presents and analyzes waveforms, spectrograms, and signal polarization, highlighting the importance of local effects.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
J. A. Parera-Portell, F. D. L. Mancilla, J. Almendros, J. Morales, D. Stich
Summary: We analyzed the lithospheric structure of the Bransfield Strait in West Antarctica using P-wave receiver function analysis and data from 31 temporary and permanent stations. Our main finding is a 15 km tear in the Phoenix slab, which coincides with the epicenters of the 2020-2021 Orca earthquake swarm. Teleseismic wave modeling suggests that the earthquakes occurred at the base of the crust, indicating that the swarm might have been triggered by active underplating through the slab tear. Evidence of underplating and a low velocity zone in the mantle wedge was found. Average crustal thickness and Vp/Vs values were similar to those of extended continental crust.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Chenxing Luo, Jeroen Tromp, Renata M. Wentzcovitch
Summary: This study reviews the thermodynamic definition of the third-order elastic tensor and proposes using an effective third-order elastic tensor. An explicit expression for the effective third-order elastic tensor is given and verified. By extending the ab initio approach, we evaluate the strain-induced changes in SOECs and pressure derivatives of SOECs, and confirm the validity of our theory through comparisons with numerically calculated values.
Meeting Abstract
Obstetrics & Gynecology
M. Van den Berg, C. Beerendonk, S. Kaal, C. Mandigers, T. Schuurman, J. Tol, J. Tromp, M. Van der Vorst, D. Braat, R. Hermens
HUMAN REPRODUCTION
(2022)
Article
Environmental Sciences
Federica Magnoni, Emanuele Casarotti, Dimitri Komatitsch, Raffaele Di Stefano, Maria Grazia Ciaccio, Carl Tape, Daniele Melini, Alberto Michelini, Antonio Piersanti, Jeroen Tromp
Summary: Through ground motion recordings and seismic tomography, we have gained a more accurate understanding of the subsurface structure of the Italian lithosphere. The research reveals the distribution of fluids and gases in correlation with seismic activity, supports the hypothesis of a deep reservoir feeding the Mt. Etna volcano, and uncovers the complex lithosphere and tectonic evolution of the Adriatic plate.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Article
Geochemistry & Geophysics
Qiancheng Liu, Stephen Beller, Wenjie Lei, Daniel Peter, Jeroen Tromp
Summary: Full-waveform inversion is crucial in mapping geophysical subsurface structures, but lacks proper uncertainty quantification in current applications. This study enhances the BFGS algorithm for uncertainty quantification in large-scale applications, combining it with randomized singular value decomposition to obtain a low-rank approximation of the inverse Hessian. This approach is efficient and memory-affordable, demonstrating applicability for large-scale FWI and uncertainty quantification.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)