Article
Geochemistry & Geophysics
Solvi Thrastarson, Dirk-Philip Van Herwaarden, Lion Krischer, Christian Boehm, Martin van Driel, Michael Afanasiev, Andreas Fichtner
Summary: This paper presents a new method of global-scale full-waveform inversion (FWI) that significantly reduces computational cost without sacrificing rigor. The method utilizes data-adaptation and application-oriented specialization on both simulation and measurement levels. The authors also demonstrate the effectiveness of the method by inverting seismic waveforms for 3-D whole-mantle structure and constructing a global FWI model.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
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
Armando Espindola-Carmona, Ridvan Oersvuran, P. Martin Mai, Ebru Bozdag, Daniel B. Peter
Summary: Improving the resolution of seismic anelastic models is crucial for understanding the Earth's subsurface structure and dynamics. Seismic attenuation plays a vital role in estimating water content, partial melting, and temperature variations in the Earth's crust and mantle. However, seismic attenuation tomography models tend to have lower resolution compared to seismic wave-speed models.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
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)
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
Youcai Yu, Jidong Yang, Jianping Huang, Weiqi Wang, Shanyuan Qin, Zhenchun Li
Summary: Conventional full-waveform seismic inversion (FWI) tries to estimate a subsurface model by minimizing the L-2-norm misfit between observed and synthetic data. However, it may produce a spurious model if the initial model is far from the true model. To mitigate this problem, a novel FWI scheme using a high-dimensional local coherence misfit function is presented. Numerical experiments show that this scheme has a better tolerance to inaccurate starting models and is less sensitive to cycle-skipping issues compared with the conventional FWI method.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Geochemistry & Geophysics
Sarouyeh Khoshkholgh, Andrea Zunino, Klaus Mosegaard
Summary: Utilizing a global proposal distribution informed by the physics of the problem can significantly enhance the performance of the MCMC algorithm, especially when solving highly nonlinear inverse problems with vast model spaces. This improvement mainly manifests in a dramatic reduction in burn-in time and a better ability to explore high-probability regions.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
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
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
Yuanyuan Li, Tariq Alkhalifah
Summary: Full waveform inversion has potential in recovering high-resolution subsurface models, with extended waveform inversion providing an effective way to mitigate cycle skipping. By treating the matching filter as an independent variable and extending the search space, a more accurate direction for velocity updates can be obtained.
GEOPHYSICAL PROSPECTING
(2021)
Article
Geochemistry & Geophysics
H. S. Aghamiry, F. W. Mamfoumbi-Ozoumet, A. Gholami, S. Operto
Summary: Full waveform inversion (FWI) requires accurate estimation of source signatures, which are crucial for subsurface model inversion. Recent extended-space FWI methods improve estimation accuracy by relaxing the wave equation and utilizing data assimilation to handle cycle skipping. This study proposes a simple method to efficiently estimate source signatures during extended FWI, bypassing issues with direct and block iterative methods.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Kota Mukumoto, Takeshi Tsuji
Summary: We have developed a crustal shear wave velocity model for central Japan by using a large seismic data volume and full-waveform tomographic inversion. Our model accurately represents the known geology and lithology of the region, and reveals various subsurface features including volcanic fluids, dehydration fluids, and sedimentary basins. Unlike previous models, which relied on first-arrival tomography, our model explicitly computes the full seismic wavefield, making it more suitable for high-resolution imaging in the 10-50s period range.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Leon Diekmann, Ivan Vasconcelos, Tristan van Leeuwen
Summary: Full waveform inversion and least-squares reverse time migration are commonly used for seismic wave imaging, relying on the Born approximation to compute gradients and update models. We propose using the Marchenko integral to obtain an alternative linear equation that includes all orders of scattering. This new linearization strategy, although relying on the quality of the Marchenko-derived Green's functions, produces slightly better inverted models than the single-scattering approximation.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
H. S. Aghamiry, A. Gholami, S. Operto
Summary: Regularization is essential for solving non-linear ill-posed inverse problems in geosciences. This paper proposes two generic optimization algorithms to implement arbitrary regularization, recasting the task as denoising. The proximal Newton method is used for solving the inverse problem, with two splitting algorithms proposed for handling the Hessian matrix in regularized least-squares optimization.
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
Mathematics, Applied
Nikolay Yavich, Nikolay Khokhlov, Mikhail Malovichko, Michael S. Zhdanov
Summary: Two preconditioning approaches for solving the three-dimensional Helmholtz equation were compared in this study, with the second approach showing faster convergence and better performance for problems involving millions of unknowns. The CO-based solver demonstrated efficient handling of highly heterogeneous media at different frequencies, outperforming the open-source parallel sweeping preconditioner in terms of speed and memory consumption.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2021)
Editorial Material
Geochemistry & Geophysics
Michael S. Zhdanov
Article
Geochemistry & Geophysics
Mikhail S. Malovichko, Andrey Tarasov, Nikolay B. Yavich, Konstantin Titov
Summary: The self-potential (SP) method in hydrogeophysics has gained interest, and we have developed a novel approach for SP data inversion. Our method formulates the inversion problem as an optimal control problem and translates it into a variational system, resulting in a sparse block matrix. It can be efficiently solved using direct sparse solvers or preconditioned iterative solvers. Numerical experiments show that our approach may serve as a rapid and reliable tool for large-scale SP inverse problems and can easily be extended to other geophysical linear inverse problems.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Mechanics
Vasily Golubev, Alexey Shevchenko, Nikolay Khokhlov, Igor Petrov, Mikhail Malovichko
Summary: This paper presents a novel numerical scheme for simulating acoustic waves in heterogeneous 2D media, and demonstrates its accuracy in handling discontinuous material parameters. The scheme is evaluated through numerical experiments and found to exhibit second-order convergence. It is successfully applied to the Sukhoi Log gold deposit model and the Marmousi model, providing a valuable tool for precise simulation of wavefields in complex media with discontinuous parameters.
INTERNATIONAL JOURNAL OF APPLIED MECHANICS
(2022)
Article
Computer Science, Interdisciplinary Applications
N. Yavich, N. Koshev, M. Malovichko, A. Razorenova, M. Fedorov
Summary: In this paper, the performance of the mixed-hybrid finite element method (MHFEM) for EEG and MEG modeling is assessed. The study concludes that although MHFEM is computationally demanding, it improves the accuracy of modeling on low-resolution head models compared to the conventional nodal finite element method (P-1 FEM).
IEEE TRANSACTIONS ON MEDICAL IMAGING
(2022)
Article
Geochemistry & Geophysics
Michael S. Zhdanov, Xiaolei Tu, Martin Cuma
Summary: The inversion of geophysical data is a complex ill-posed problem due to uncertainty and ambiguity. Cooperative inversion, based on multiple geophysical data, can reduce this uncertainty by considering a shared earth model. This paper introduces a new approach to cooperative geophysical inversion without the need for prior knowledge of empirical or statistical relationships. The method uses a joint minimum entropy stabilizer to produce a consistent image of the same geological structure expressed in different geophysical data.
NEAR SURFACE GEOPHYSICS
(2022)
Article
Geochemistry & Geophysics
Michael S. Zhdanov, Michael Jorgensen, Le Wan
Summary: This novel approach allows for three-dimensional gravity inversion in the presence of a sediment-basement interface with a strong density contrast. It incorporates known information about the basement depth and uses it as a constraint in the inversion process. The results provide a 3D density model of the top layers of the Earth's crust.
Article
Geochemistry & Geophysics
Nikolay I. Khokhlov, Alena Favorskaya, Vladislav Furgailo
Summary: This article introduces a new method for calculating wave scattering from fractured geological clusters using overlapping curvilinear grids. The results of testing this method show high accuracy and applicability in most cases.
Article
Chemistry, Analytical
Ekaterina Skidchenko, Anna Butorina, Maxim Ostras, Petr Vetoshko, Alexey Kuzmichev, Nikolay Yavich, Mikhail Malovichko, Nikolay Koshev
Summary: Recently, a new kind of sensor called solid-state yttrium-iron garnet magnetometer (YIGM) has been used in magnetoencephalography (MEG). Its feasibility was demonstrated in an experiment recording alpha-rhythm. This paper analyzes lead-field matrices for different possible on-scalp sensor layouts using YIGMs, comparing it with existing MEG systems based on SQUIDs and OPMs in terms of signal-to-noise ratio (SNR) and total information capacity (TiC). The results show that YIGMs outperform SQUIDs and OPMs at respective noise levels, but the current noise levels of YIGM sensors are insufficient for constructing a multichannel YIG-MEG system.
Article
Geochemistry & Geophysics
Zhengwei Xu, Rui Wang, Michael S. Zhdanov, Xuben Wang, Jun Li, Bing Zhang, Shengxian Liang, Yang Wang
Summary: The study and assessment of subsurface density distribution are crucial for mining and oil and gas exploration. 3-D inversion of observed gravity and gravity gradiometry data is used for this purpose. The nonuniqueness and instability of solutions due to the ill-posedness of the geophysical inverse problem pose challenges to inversion. This article proposes a fast reconstruction method using ResUnet technology for subsurface density models, which has shown promising results in synthetic datasets.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Geochemistry & Geophysics
Juntao Lu, Xuben Wang, Zhengwei Xu, Michael S. Zhdanov, Ming Guo, Minqiang Teng, Zhen Liu
Summary: This article introduces a quasi-2D inversion scheme to extract resistivity and IP parameters from SATEM data. The proposed scheme utilizes a fast semi-analytical method for Jacobian matrix calculation and employs a staged inversion strategy with lateral constraints, which improves inversion stability and recovers underground resistivity and IP property distributions.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Geochemistry & Geophysics
Endre Nadasi, Alexander Gribenko, Michael S. Zhdanov
Summary: This paper presents a regularized method for 3D inversion of magnetotelluric (MT) data using the Gauss-Newton algorithm in the data space. It takes into account the distortion effects of near-surface geoelectrical inhomogeneities by simultaneously inverting the MT impedance tensor and tipper. The method was successfully applied to a large-scale 3D inversion of MT data collected over the Western Superior region, identifying several conductive anomalies in the Earth's crust and upper mantle.
PURE AND APPLIED GEOPHYSICS
(2022)
Article
Mathematics
I. B. Petrov, P. Stognii, N. Khokhlov
Summary: Fractured media and hydraulic fracturing are important for oil field exploration, with mathematical modeling methods aiding in the study of such heterogeneities. The Schoenberg fracture model considers fluid characteristics inside the fracture and an algorithm has been developed to compute medium parameters at the fracture boundary.
DOKLADY MATHEMATICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Tian Liang, Lin Fu
Summary: In this work, a new shock-capturing framework is proposed based on a new candidate stencil arrangement and the combination of infinitely differentiable non-polynomial RBF-based reconstruction in smooth regions with jump-like non-polynomial interpolation for genuine discontinuities. The resulting scheme achieves high order accuracy and resolves genuine discontinuities with sub-cell resolution.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Lukas Lundgren, Murtazo Nazarov
Summary: In this paper, a high-order accurate finite element method for incompressible variable density flow is introduced. The method addresses the issues of saddle point system and stability problem through Schur complement preconditioning and artificial compressibility approaches, and it is validated to have high-order accuracy for smooth problems and accurately resolve discontinuities.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Gabriele Ciaramella, Laurence Halpern, Luca Mechelli
Summary: This paper presents a novel convergence analysis of the optimized Schwarz waveform relaxation method for solving optimal control problems governed by periodic parabolic PDEs. The analysis is based on a Fourier-type technique applied to a semidiscrete-in-time form of the optimality condition, which enables a precise characterization of the convergence factor at the semidiscrete level. The behavior of the optimal transmission condition parameter is also analyzed in detail as the time discretization approaches zero.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Jonas A. Actor, Xiaozhe Hu, Andy Huang, Scott A. Roberts, Nathaniel Trask
Summary: This article introduces a scientific machine learning framework that uses a partition of unity architecture to model physics through control volume analysis. The framework can extract reduced models from full field data while preserving the physics. It is applicable to manifolds in arbitrary dimension and has been demonstrated effective in specific problems.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Nozomi Magome, Naoki Morita, Shigeki Kaneko, Naoto Mitsume
Summary: This paper proposes a novel strategy called B-spline based SFEM to fundamentally solve the problems of the conventional SFEM. It uses different basis functions and cubic B-spline basis functions with C-2-continuity to improve the accuracy of numerical integration and avoid matrix singularity. Numerical results show that the proposed method is superior to conventional methods in terms of accuracy and convergence.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Timothy R. Law, Philip T. Barton
Summary: This paper presents a practical cell-centred volume-of-fluid method for simulating compressible solid-fluid problems within a pure Eulerian setting. The method incorporates a mixed-cell update to maintain sharp interfaces, and can be easily extended to include other coupled physics. Various challenging test problems are used to validate the method, and its robustness and application in a multi-physics context are demonstrated.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Xing Ji, Fengxiang Zhao, Wei Shyy, Kun Xu
Summary: This paper presents the development of a third-order compact gas-kinetic scheme for compressible Euler and Navier-Stokes solutions, constructed particularly for an unstructured tetrahedral mesh. The scheme demonstrates robustness in high-speed flow computation and exhibits excellent adaptability to meshes with complex geometrical configurations.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Alsadig Ali, Abdullah Al-Mamun, Felipe Pereira, Arunasalam Rahunanthan
Summary: This paper presents a novel Bayesian statistical framework for the characterization of natural subsurface formations, and introduces the concept of multiscale sampling to localize the search in the stochastic space. The results show that the proposed framework performs well in solving inverse problems related to porous media flows.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Jacob Rains, Yi Wang, Alec House, Andrew L. Kaminsky, Nathan A. Tison, Vamshi M. Korivi
Summary: This paper presents a novel method called constrained optimized DMD with Control (cOptDMDc), which extends the optimized DMD method to systems with exogenous inputs and can enforce the stability of the resulting reduced order model (ROM). The proposed method optimally places eigenvalues within the stable region, thus mitigating spurious eigenvalue issues. Comparative studies show that cOptDMDc achieves high accuracy and robustness.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Andrea La Spina, Jacob Fish
Summary: This work introduces a hybridizable discontinuous Galerkin formulation for simulating ideal plasmas. The proposed method couples the fluid and electromagnetic subproblems monolithically based on source and employs a fully implicit time integration scheme. The approach also utilizes a projection-based divergence correction method to enforce the Gauss laws in challenging scenarios. Numerical examples demonstrate the high-order accuracy, efficiency, and robustness of the proposed formulation.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Junhong Yue, Peijun Li
Summary: This paper proposes two numerical methods (IP-FEM and BP-FEM) to study the flexural wave scattering problem of an arbitrary-shaped cavity on an infinite thin plate. These methods successfully decompose the fourth-order plate wave equation into the Helmholtz and modified Helmholtz equations with coupled conditions on the cavity boundary, providing an effective solution to this challenging problem.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
William Anderson, Mohammad Farazmand
Summary: We develop fast and scalable methods, called RONS, for computing reduced-order nonlinear solutions. These methods have been proven to be highly effective in tackling challenging problems, but become computationally prohibitive as the number of parameters grows. To address this issue, three separate methods are proposed and their efficacy is demonstrated through examples. The application of RONS to neural networks is also discussed.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Marco Caliari, Fabio Cassini
Summary: In this paper, a second order exponential scheme for stiff evolutionary advection-diffusion-reaction equations is proposed. The scheme is based on a directional splitting approach and uses computation of small sized exponential-like functions and tensor-matrix products for efficient implementation. Numerical examples demonstrate the advantage of the proposed approach over state-of-the-art techniques.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Sebastiano Boscarino, Seung Yeon Cho, Giovanni Russo
Summary: This work proposes a high order conservative semi-Lagrangian method for the inhomogeneous Boltzmann equation of rarefied gas dynamics. The method combines a semi-Lagrangian scheme for the convection term, a fast spectral method for computation of the collision operator, and a high order conservative reconstruction and a weighted optimization technique to preserve conservative quantities. Numerical tests demonstrate the accuracy and efficiency of the proposed method.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Jialei Li, Xiaodong Liu, Qingxiang Shi
Summary: This study shows that the number, centers, scattering strengths, inner and outer diameters of spherical shell-structured sources can be uniquely determined from the far field patterns. A numerical scheme is proposed for reconstructing the spherical shell-structured sources, which includes a migration series method for locating the centers and an iterative method for computing the inner and outer diameters without computing derivatives.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)