Article
Geochemistry & Geophysics
N. Hedjazian, Y. Capdeville, T. Bodin
Summary: Seismic imaging techniques are limited by the maximum frequency in observed waveforms, leading to a smoothed, effective version of the true medium. Homogenization theory helps compute effective properties of mediums with small-scale heterogeneities, and can be used in full waveform inversion. Two-stage multiscale methods break down the seismic imaging problem, revealing the benefits of using homogenization theory.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Bin Liu, Zhifei Gong, Fengkai Zhang, Xinji Xu, Yang Zhao, Lei Chen
Summary: This paper proposes an improved tunnel FWI method by adopting N-order time integral wavefield and normalized integration objective function method to enhance stability and reduce dependence on the initial model. The effectiveness and reliability of the method in tunnel detection environments are verified through application to synthetic models and field data.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Matteo Ravasi, Claire Birnie
Summary: Structural seismic interpretation and quantitative characterization are interconnected processes that jointly estimate subsurface properties and a segmented representation of the subsurface based on user-defined classes. The inversion is primed with prior knowledge and constrained by actual seismic measurements, optimizing the quantities alternately to generate a consistent structural framework. The proposed method shows effectiveness through numerical examples on synthetic and field data sets.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Matteo Ravasi, Claire Birnie
Summary: Structural seismic interpretation and quantitative characterization are closely related processes that aim to estimate subsurface properties. A new approach to this problem is proposed in this work, utilizing user-defined macroclasses for subsurface estimation and seismic measurements for constraint. The method shows effectiveness through numerical examples on synthetic and field data sets.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Nienke Blom, Phil-Simon Hardalupas, Nicholas Rawlinson
Summary: This study investigates the impact of errors in earthquake source parameters on the tomographic inverse problem and proposes strategies to mitigate artefacts caused by these errors. The results show that errors in source location and moment tensor can lead to significant time-shifts and artefacts in the tomographic models. Mitigation strategies include removing the source region from the gradient and discarding traces with small amplitudes. Horizontal mislocation is the most problematic type of error.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
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
A. Espindola-Carmona, Daniel Peter, C. Ortiz-Aleman
Summary: Recent seismic imaging studies of the Mexican subduction zone have utilized over 3,300 seismic records from 74 regional earthquakes to analyze the three-dimensional seismic wave velocity structures in Central and Southern Mexico, revealing various underground features such as the geometry of the Cocos slab and the presence of horizontal structures in the lower crust and shallow upper mantle. These findings provide insights into slow earthquakes and seismic velocity anomalies in the region.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Dirk Philip van Herwaarden, Michael Afanasiev, Solvi Thrastarson, Andreas Fichtner
Summary: We propose a new approach to full-waveform inversion that allows for continuous assimilation of growing data volumes without the need to reinvert all data. Specifically designed for seismological applications, our method utilizes a dynamic mini-batch stochastic L-BFGS to sequentially add new data while maintaining convergence and consistency in model fit measurement.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Yongming Lu, Wei Zhang
Summary: Traveltime computations are crucial in seismic data processing applications, and a fast and efficient method is developed in this study to solve the issues in anisotropic media. By transforming the quartic slowness equation into a quadratic one, the computational efficiency is greatly improved, making it suitable for calculating first-arrival traveltimes in 3-D VTI media.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Chao Lyu, Yann Capdeville, David Al-Attar, Liang Zhao
Summary: In the field of seismic imaging, full waveform inversion (FWI) is popular due to its lower numerical cost, but the acoustic approximation may lead to non-uniqueness issues. Therefore, results of acoustic inversions based on hand-limited data should be interpreted with caution.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Zhisheng Zheng, Yang Liu, Cai Liu
Summary: In this study, f-x and f-x-y streaming prediction filters (SPFs) were proposed to reconstruct missing seismic traces without iterations. An analytic solution to the overdetermined least-squares problem with local smoothness constraints was directly derived in the frequency domain based on the streaming computation framework. Different processing paths and filter forms were introduced to reduce interference and improve the accuracy of filter coefficients. A two-step interpolation strategy was utilized to ensure effective interpolation of irregularly missing traces. Numerical examples demonstrated the effectiveness of the proposed methods in recovering missing traces and the advantages of frequency domain SPFs in high-dimensional seismic data interpolation with low computational cost and reasonable non-stationary signal reconstruction.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Henry Brett, Rhys Hawkins, Lauren Waszek, Karen Lythgoe, Arwen Deuss
Summary: Body wave observations of the Earth's inner core reveal strong seismic heterogeneity, particularly in the western region. By employing transdimensional Markov Chain Monte Carlo seismic tomography, we identify the presence of anisotropic hemispheres and a tilted innermost inner core. These findings are crucial for advancing our understanding of the Earth's internal structure.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Christian Poppeliers, Leiph Preston
Summary: This study presents an analysis of combining translational and rotational seismic data to invert for the time-variable source time functions corresponding to the components of the seismic moment tensor. Numerical experiments are conducted to simulate data from an underground explosion and a co-located double couple shear source, recorded on surface-mounted seismometers. The results show that the uncertainty of the estimated seismic source parameters increases when rotational seismic motions are added to the inversion with a constant number of data channels. However, when a fixed number of seismic stations are used, adding rotational seismic motions to the inversion decreases the uncertainty of the estimated seismic source parameters.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Shoji Sekiguchi
Summary: Limiting the number of valid nodes around a reference ray can greatly reduce the calculation time of the shortest-path method. The modified calculation method shows small average traveltime and ray path differences in velocity models. Improved travel time and ray path results can be achieved through iterative calculations and utilizing more neighbor nodes.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Bjorn Ursin, Nathalie Favretto-Cristini, Paul Cristini
Summary: Seismic data recorded in complex geological environments require compensation for geometrical spreading before AVO/AVA analysis, and interface effects should also be compensated. 3-D numerical simulations validate analytical derivations, showing that interface curvature has a significant impact on reflected events. This highlights the importance of considering interface effects in AVA/AVO analysis to avoid misinterpretation.
GEOPHYSICAL JOURNAL INTERNATIONAL
(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
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
Multidisciplinary Sciences
Roberto Benzi, Ilaria Castaldi, Federico Toschi, Jeannot Trampert
Summary: This paper investigates a simplified model of turbulence for large Reynolds numbers driven by a constant power energy input on large scales. The study reveals two distinct phases in the behaviour of the kinetic energy: a laminar phase and abrupt avalanche-like energy drops phase. The probability distributions of these phases exhibit scaling behaviour, and a scaling argument suggests a relationship between them.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Geochemistry & Geophysics
J. H. E. de Jong, H. Paulssen, T. van Leeuwen, J. Trampert
Summary: Receiver functions have long been used to study Earth's major discontinuities. The traditional assumptions for mapping locations in the subsurface have been found to have limitations, but the use of adjoint tomography provides a potential solution. Sensitivity kernels for P-to-S converted waves have been calculated, revealing differences in sensitivity to P-wave speed and S-wave speed. The well-known trade-off between depth of the discontinuity and wave speed has also been observed, but can be significantly reduced by considering longer waveforms that include more surface reverberations.
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
Geochemistry & Geophysics
R. Hawkins, M. H. Khalid, K. Smetana, J. Trampert
Summary: The computational cost of full waveform simulation in seismological contexts is high and requires large clusters of computers. We focus on model order reduction (MOR) method, which projects the full waveform system onto a lower dimensional space to reduce computational and memory requirements, at the cost of approximation errors. Inspired by normal mode (NM) theory, we use seismic wave equation eigenmodes for MOR. We demonstrate the application of free body oscillations and Petrov-Galerkin projection in regional scale problems using advanced eigensolvers for MOR, and its potential in future time-critical applications like seismic hazard monitoring.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geosciences, Multidisciplinary
Eldert Fokker, Elmer Ruigrok, Rhys Hawkins, Jeannot Trampert
Summary: This study presents a new technique of four-dimensional pore pressure monitoring using passive image interferometry. By linking surface-wave velocity changes to pore pressure variations through sensitivity kernels, we can accurately invert time-lapse seismic velocity changes for hydrological pore pressure variations. The method is successfully applied in the Groningen region of the Netherlands, showing good recovery of pore pressure variations in the upper 200 m of the subsurface.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
Dirk-Philip van Herwaarden, Solvi Thrastarson, Vaclav Hapla, Michael Afanasiev, Jeannot Trampert, Andreas Fichtner
Summary: In this study, a seismic model of the Africa Plate is constructed using the full-waveform inversion technique. The model is used for geodynamic and geochemical interpretation, earthquake-induced ground motion predictions, and earthquake source inversion. The data from 397 earthquakes and 184,356 source-receiver pairs are inverted to image the tectonic features of the Africa Plate. A new strategy to assess model uncertainty is proposed.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
J. H. E. de Jong, H. Paulssen, J. Trampert
Summary: Teleseismic receiver functions are used to map the depth and topography of major discontinuities in the Earth's mantle. Adjoint method of full waveform inversion is applied to calculate sensitivity kernels for receiver functions. These kernels show the influence of model parameters on the waveforms. Synthetic data is calculated for P410s and P660s phases and volumetric and boundary sensitivity kernels are obtained. The results indicate that receiver functions are sensitive to the topography of discontinuities, but an incorrect velocity model can lead to errors in the projected topography.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Mineralogy
Ashim Rijal, Laura Cobden, Jeannot Trampert, Hauke Marquardt, Jennifer M. Jackson
Summary: The shear properties of mantle minerals are crucial for understanding planetary interiors. In this study, a data-driven approach using a neural network is proposed to learn the relationship between pressure, temperature, and shear modulus without relying on a predefined equation. The results show that different experimental data can lead to inconsistent predictions, and the prior assumption of equation form can constrain the shear modulus even if it diverges from the actual behavior of the Earth.
EUROPEAN JOURNAL OF MINERALOGY
(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
Geosciences, Multidisciplinary
Jeannot Trampert, Roberto Benzi, Federico Toschi
Summary: In this study, we reanalyzed the induced seismicity data from the Groningen gas reservoir and found that the distributions of seismic moments and interevent times exhibited power law behavior. By constraining the average loading of elastic energy within the reservoir, we can explain the occurrence of seismic events. We also proposed a new machine learning approach for distinguishing correlated and independent events.
NETHERLANDS JOURNAL OF GEOSCIENCES-GEOLOGIE EN MIJNBOUW
(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)