Article
Geochemistry & Geophysics
C. Alder, E. Debayle, T. Bodin, A. Paul, L. Stehly, H. Pedersen
Summary: Studying seismic anisotropy in the lithosphere has revealed significant radial anisotropy beneath the Apennines in Europe, differing from previous large-scale studies. This radial anisotropy is attributed to ductile horizontal flow in response to recent and present-day extension in the region.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
P. Moulik, V Lekic, B. Romanowicz, Z. Ma, A. Schaeffer, T. Ho, E. Beucler, E. Debayle, A. Deuss, S. Durand, G. Ekstrom, S. Lebedev, G. Masters, K. Priestley, J. Ritsema, K. Sigloch, J. Trampert, A. M. Dziewonski
Summary: Global variations in the propagation of surface waves provide unique constraints on the source properties and structure of the Earth's mantle. This study aims to construct a reference data set of multimode dispersion measurements by reconciling large and diverse catalogues of surface wave dispersion. The study finds that the measurements of fundamental-mode dispersion are internally consistent, but the agreement deteriorates for overtones.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Celia L. Eddy, Goran Ekstrom, Meredith Nettles
Summary: This study presents a new 3-D model of seismic velocity and anisotropy in the Pacific upper mantle, PAC13E. The research finds strong radial and azimuthal anisotropy in the lithosphere, with different alignment patterns in the lithosphere and asthenosphere. Additionally, the presence of shear in the asthenosphere not aligned with absolute-plate-motion directions is observed.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
J-P Montagner, G. Burgos, Y. Capdeville, E. Beucler, A. Mocquet
Summary: The mantle transition zone, located between 410 and 1000 km in depth, plays a crucial role in mantle convection processes by acting as a boundary layer within the mantle. Depth variations of seismic anisotropies allow for the detection of boundary layers within the mantle. A new 3D anisotropy model of the mantle down to 1200 km in depth has been developed, revealing significant seismic anisotropy below subduction zones around the Pacific Ocean and in a large area beneath eastern Eurasia.
Article
Environmental Sciences
Caroline M. Eakin
Summary: Quasi-Love wave scattering is used to identify gradients in seismic anisotropy in the mantle beneath Australia, suggesting major lithospheric boundaries and modified mantle flow in the ocean-continent transition zone. The investigation reveals pervasive fossilized lithospheric anisotropy within the Australian continent, with lateral anisotropic gradients potentially indicating the edge of thick continental lithosphere or small-scale dynamic processes in the asthenosphere.
COMMUNICATIONS EARTH & ENVIRONMENT
(2021)
Article
Geochemistry & Geophysics
Hao Rao, Yinhe Luo, Kaifeng Zhao, Yingjie Yang
Summary: The study introduces an alternative method called the two-station C-2 method, which uses a single station as a virtual source to retrieve surface wave phase velocities between asynchronous stations. Results show that this method can obtain reliable phase velocity measurements and can significantly improve ray path coverage and resolution in ambient noise tomography for areas between asynchronous seismic arrays.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Fabrizio Magrini, Sebastian Lauro, Emanuel Kastle, Lapo Boschi
Summary: In order to enhance our understanding of the structure of the Earth's interior, seismologists utilize large amounts of data and automated tools for analysis. This study introduces SeisLib, an open-source Python package for multiscale seismic imaging. The functionalities of SeisLib, which include surface-wave tomography based on seismic ambient noise and teleseismic earthquakes, are demonstrated through theoretical explanations, algorithms, and applications to seismic data from North America. The results highlight the robustness and computational efficiency of SeisLib.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Yongsheng Liu, Ping Tong
Summary: This study investigated the seismic anisotropy in the crust of northern California using seismic techniques, revealing the presence of different geological units and parallel fault zones. The results showed significant velocity contrasts, possibly indicating different geological structures and stress states.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Graca Silveira, Nuno Afonso Dias, Sergey Kiselev, Eleonore Stutzmann, Susana Custodio, Martin Schimmel
Summary: This study presents a new high-resolution three-dimensional shear wave velocity model of the crust and uppermost mantle in Portugal. The model contributes to a better understanding of the seismicity and geological structures in Portugal.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Malgorzata Chmiel, Philippe Roux, Marc Wathelet, Thomas Bardainne
Summary: The proposed method utilizes densely sampled active-source arrays and combines elements from active-source seismic-wave interferometry, full waveform inversion, and dense-array processing. The seismic Michelson interferometer (SMI) can iteratively invert the medium without the need for travel time measurements or spatial regularization, providing high-resolution phase-velocity maps and error estimation efficiently. It can be applied to traditional surface wave tomography studies and easily extended to virtual source gathers of ambient-noise-based studies with dense arrays.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Emma L. Chambers, Nicholas Harmon, Catherine A. Rychert, Ryan J. Gallacher, Derek Keir
Summary: Understanding the dynamics and evolution of continental rifting is crucial for comprehending plate tectonics. By inverting seismic data, this study reveals large-scale magmatic activity in the rift area and suggests that melt infiltration may occur before significant deformation. Additionally, the migration process of the melt is dynamic and may happen laterally as well as within the rift.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
I. Barone, G. Cassiani, A. Ourabah, J. Boaga, M. Pavoni, R. Deiana
Summary: In this paper, the analysis of passive seismic noise recorded around the Scrovegni Chapel in Padua using a dense 2-D network of autonomous seismic nodes is presented. The ambient noise is characterized and cross-correlation analysis is performed to retrieve virtual source gathers. Traveltimes are extracted and Eikonal tomography is run to retrieve phase velocity maps and azimuthal anisotropy. The results obtained from active and passive methods are compared and discussed, and a strategy for the integration of passive and active information is proposed. The joint analysis improves the accuracy of the shear wave velocity model at depth.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Simon Schneider, Arwen Deuss
Summary: Spectra of whole Earth oscillations or normal modes provide important constraints on Earth's large-scale structure. The most convenient way to include normal mode constraints in global tomographic models is by using splitting functions or structure coefficients. This study expands on previous splitting function research, specifically focusing on toroidal-mode overtone observations to provide new constraints on mantle structure.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Zhi Guo, Xing Gao
Summary: In this study, the isotropic and azimuthal anisotropic crustal structure of the South China block is imaged using continuous seismic ambient noise recorded by dense permanent seismic stations. The results show the lateral changes in the isotropic crustal structure are consistent with surface geology, while the azimuthal anisotropy reveals more details about the tectonic evolution of the South China block.
Article
Geochemistry & Geophysics
N. A. Simmons, S. C. Myers, C. Morency, A. Chiang, D. R. Knapp
Summary: SPiRaL is a global-scale model capturing wave speeds and anisotropy variations, with the ability to accurately predict event locations and long-period waveform dispersion. It serves as a starting model for full-waveform inversion applications, fitting waves over broad regions with the potential to cover the globe.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Emanuel D. Kastle, A. El-Sharkawy, L. Boschi, T. Meier, C. Rosenberg, N. Bellahsen, L. Cristiano, C. Weidle
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2018)
Article
Geography, Physical
Andreas Kohler, Valerie Maupin, Christopher Nuth, Ward van Pelt
ANNALS OF GLACIOLOGY
(2019)
Article
Geochemistry & Geophysics
A. Scharf, F. Mattern, D. Moraetis, I. Callegari, C. Weidle
Article
Geochemistry & Geophysics
Kaiming Wang, Laiyu Lu, Valerie Maupin, Zhifeng Ding, Chen Zheng, Shijun Zhong
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2020)
Article
Geochemistry & Geophysics
Amr El-Sharkawy, Thomas Meier, Sergei Lebedev, Jan H. Behrmann, Mona Hamada, Luigia Cristiano, Christian Weidle, Daniel Koehn
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2020)
Article
Geochemistry & Geophysics
Valerie Maupin
Summary: Regional body-wave tomography is a popular tomographic method, but asynchronous network deployments may introduce large-scale biases. By improving the formulation of sensitivity kernels, these biases can be mitigated.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
D. Ninkabou, P. Agard, C. Nielsen, J. Smit, C. Gorini, M. Rodriguez, B. Haq, N. Chamot-Rooke, C. Weidle, C. Ducassou
Summary: The northern Oman margin plays a key role in understanding the emplacement of the Semail Ophiolite and obduction processes. Different regions along the margin show distinct geological histories.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Hans Thybo, Nevra Bulut, Michael Grund, Alexandra Mauerberger, Anna Makushkina, Irina M. Artemieva, Niels Balling, Olafur Gudmundsson, Valerie Maupin, Lars Ottemoller, Joachim Ritter, Frederik Tilmann
Summary: The ScanArray international collaborative program collected broadband seismological data at 192 locations in the Baltic Shield from 2012 to 2017, aiming to provide constraints on the structure of the lithospheric crust and mantle, as well as sublithospheric upper mantle. The high-quality recordings are used for various seismological analyses to study the lithospheric and deep structure and their effects on topographic changes and geological-tectonic evolution in the region.
SEISMOLOGICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
N. Bulut, H. Thybo, V Maupin
Summary: This study presents a P-wave velocity model of the upper mantle in Fennoscandia obtained from finite-frequency body-wave tomography. The model reveals a strong negative velocity anomaly in Norway, which may provide isostatic support to the high topography of the Scandinavian mountain range. Additionally, strong positive velocity anomalies are observed around the southern Bothnian Bay and the Baltic Sea.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
L. Wiesenberg, C. Weidle, A. El-Sharkawy, M. Timko, S. Lebedev, T. Meier
Summary: Ambient seismic noise tomography is a well-established tool for imaging seismic properties of the Earth's crust. This paper presents an automated algorithm that fits the phase of the Hankel function to the phase of the causal symmetric part of the cross-correlation function (CCF) in order to determine phase velocity curves as continuous functions of frequency. Synthetic tests verify the reliability of the proposed method in the presence of low signal-to-noise ratio. The method is particularly useful at short inter-station distances and has been applied to waveform data from seismic stations in northern Oman.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
C. Weidle, L. Wiesenberg, A. El-Sharkawy, F. Krueger, A. Scharf, P. Agard, T. Meier
Summary: This study provides detailed information about the three-dimensional underground structure in the Semail Ophiolite region in eastern Arabia, and identifies two distinct geological units in the Arabian crust. By processing and analyzing seismological data, the study reveals the crustal variations in the Late Ophiolite region and its impact on the topography.
GEOPHYSICAL JOURNAL INTERNATIONAL
(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
C. Weidle, L. Wiesenberg, A. Scharf, P. Agard, A. El-Sharkawy, F. Krueger, T. Meier
Summary: The geodynamic evolution of Eastern Arabia consists of three main events: Pan-African plate assembly, Infracambrian and Ordovician extension, and Permian Pangean breakup and rifting. The obduction of the Semail Ophiolite during the Late Cretaceous and the subsequent relaxation of the lithosphere are also significant. Seismological observations reveal the lithospheric thickness and crustal heterogeneity of Eastern Arabia, indicating the segmentation of the crust and the impact of various tectonic events. The configuration of the lithosphere in northeastern Arabia preserves imprints from multiple geological periods.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Alexandra Mauerberger, Valerie Maupin, Olafur Gudmundsson, Frederik Tilmann
Summary: The study used the ScanArray network to analyze the propagation of Rayleigh waves in Scandinavia, finding slower phase velocities in most of Northern Europe. It also observed remarkable azimuthal variations in phase velocities in northern Scandinavia and southern Norway/Sweden, suggesting a relation to large lithospheric heterogeneity.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geography, Physical
Andreas Kohler, Christian Weidle
EARTH SURFACE DYNAMICS
(2019)