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Discrimination between icequakes and earthquakes in southern Alaska: an exploration of waveform features using random forest algorithm Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-15 Akash Kharita, Marine A Denolle, Michael E West
Summary This study examines the feature space of seismic waveforms often used in machine learning applications for seismic event detection and classification problems. Our investigation centers on the southern Alaska region, where the seismic record captures diverse seismic activity, notably from the calving of marine-terminating glaciers and tectonic earthquakes along active plate boundaries. While
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A simple weighting method for inverting earthquake source parameters using geodetic multi-source data under Bayesian algorithm Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-14 Can Xi, Leyang Wang, Xiong Zhao, Zhanglin Sun, Weifeng Zhao, Ming Pang, Fei Wu
Summary More accurate inversion of source fault geometry and slip parameters under the constraint of the Bayesian algorithm has become a research hotspot in the field of geodetic inversion in recent years. In nonlinear inversion, the determination of the weight ratio of the joint inversion of multi-source data is more complicated. In this context, this paper proposes a simple and easily generalized
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On the temperature sensitivity of near-surface seismic wave speeds: Application to the Groningen region, the Netherlands Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-13 Eldert Fokker, Elmer Ruigrok, Jeannot Trampert
Summary Subsurface temperature measurements play a crucial role, for instance, in optimizing geothermal power plants and monitoring heat-storage systems. Previous studies have demonstrated that time-lapse variations in temperature can be correlated with variations in seismic wave speeds, offering the potential for temperature monitoring via seismic surveys. However, an apparent discrepancy has emerged
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Time Scales of Glacial Isostatic Adjustment in Greenland: Is Transient Rheology Required? Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-12 Linda Pan, Jerry X Mitrovica, Glenn A Milne, Mark J Hoggard, Sarah A Woodroffe
Summary The possibility of a transient rheological response to ice age loading, first discussed in the literature of the 1980s, has received renewed attention. Transient behavior across centennial to millennial time scales has been invoked to reconcile apparently contradictory inferences of steady state (Maxwell) viscosity based on two distinct data sets from Greenland: Holocene sea-level curves and
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Relating permeability and electrical conductivity in partially saturated porous media by means of the Johnson-Koplik-Schwartz characteristic length Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-12 Thanh Duy Luong, Damien Jougnot, Santiago G Solazzi, Haoliang Luo, Nguyen Manh Hung, Nguyen Van Nghia, Phan Van Do, Luong Thi Thanh Huong
Summary In this work, we revisit the seminal concept of Johnson-Koplik-Schwartz (JKS) length Λ, i.e. a characteristic length representing an effective pore size which controls various transport-related properties of porous media, such as, the permeability and the electrical conductivity. We present a novel closed-form equation that predicts the behavior of Λ in partially saturated media, for different
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Feasibility of reservoir monitoring in the Groningen gas field using ghost reflections from seismic interferometry Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-09 Faezeh Shirmohammadi, Deyan Draganov, Aukje Veltmeijer, Milad Naderloo, Auke Barnhoorn
Summary Seismic interferometry (SI) retrieves new seismic responses, e.g., reflections, between either receivers or sources. When SI is applied to a reflection survey with active sources and receivers at the surface, non-physical (ghost) reflections are retrieved as well. Ghost reflections, retrieved from the correlation of two primary reflections or multiples from two different depth levels, are only
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Seismic scattering regimes from multiscale entropy and frequency correlations Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-08 Will Eaton, Tarje Nissen-Meyer, Claudia Haindl
Summary Seismic-wave scattering is observed, to variable degrees, on Earth, its moon, and Mars. Current scattering models and data processing typically rely on two end-member phenomena: weak single- or multiple-scattering events (ballistic) on the one hand, or intense scattering such that the wavefield retains no path information or bearing on its origin (diffuse). This study explores the existence
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Increasing accuracy of 3D geomechanical-numerical models Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-07 Moritz O Ziegler, Oliver Heidbach
Summary The current crustal stress field is of key importance to understand geodynamic processes and to assess stability aspects during subsurface usage. To provide a 3D continuous description of the stress state, linear elastic forward geomechanical-numerical models are used. These models solve the equilibrium of forces between gravitational volume forces and surfaces forces imposed mainly by plate
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On seismic gradiometric wave equation inversion for density Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-07 Marthe Faber, Andrew Curtis
Summary Material density remains poorly constrained in seismic imaging problems, yet knowledge of density would provide important insight into physical material properties for the interpretation of subsurface structures. We test ambient noise wavefield sensitivities to subsurface density contrasts through spatial and temporal wavefield gradients via Wave Equation Inversion (WEI), a form of seismic
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Slopes of the pressure dependent elastic-electrical correlations in artificial sandstones Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-06 Tongcheng Han, Tao Huang, Haiming He, Li-Yun Fu
Summary Seismic and electromagnetic explorations are two of the most successful geophysical applications for understanding the subsurface earth, and the joint interpretation of seismic and electromagnetic survey data can help to better characterize the rocks because they contain independent and complementary information about the rocks. However, the successfulness of the joint interpretation depends
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Indirect joint petrophysical inversion of shallow-seismic and multi-offset ground-penetrating radar field data Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-05 Tan Qin, Thomas Bohlen, Yudi Pan
Summary In near-surface surveys, shallow-seismic and ground-penetrating radar (GPR) full-waveform inversions (FWIs) have received increasing attention because of their ability to reconstruct high-resolution subsurface models. However, they have different sensitivities to the same targets and thus may yield conflicting geophysical parameter models. To solve this issue, we have developed an indirect
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On the elastodynamics of rotating planets Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-05 Matthew Maitra, David Al-Attar
Summary Equations of motion are derived for (visco)elastic, self-gravitating, variably-rotating planets. The equations are written using a decomposition of the elastic motion that separates the body’s elastic deformation from its net translational and rotational motion as far as possible. This separation is achieved by introducing degrees of freedom that represent the body’s rigid motions; it is made
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Unraveling the excitation mechanism of Very Long-Period (VLP) tremors in the Gulf of Guinea: Evidence for vibrations of thin surface crustal plates Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-05 Yingjie Xia, Xuping Feng, Xiaofei Chen
Summary The Gulf of Guinea exhibits a continuous emission of narrow-band and long-period signals (16, 26, and 27 seconds) on teleseismic records, yet the underlying excitation mechanism remains unclear. This study establishes a connection between these tremors and the vibration of thin, decoupled crustal plates at unexplored volcanoes in the gulf. We first formulate the damped plate oscillation equation
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Representation and interpretation about underwater sound speed gradient field in the GNSS-A observation Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-05 Yusuke Yokota, Tadashi Ishikawa, Shun-ichi Watanabe, Yuto Nakamura, Koya Nagae
Summary The Global Navigation Satellite System—Acoustic ranging combination technique (GNSS-A) is a seafloor geodetic observation technique that achieves an accuracy of centimeters by combining high-rate GNSS data with acoustic ranging. The technique determines the seafloor position by acoustic ranging between the sea surface and multiple seafloor stations, using GNSS data from the sea surface station
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The influence of an anticline structure on ambient noise spectral anomalies at an underground gas storage Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-05 Christine El Khoury, Alexandre Kazantsev, Damian Kula, Arthur Dartois, Hervé Chauris
Summary The purpose of this study is to investigate the seismic ambient noise spectral anomalies that occur near gas reservoirs. These anomalies involve a significant spectral amplification of the vertical component for frequencies generally between 1.5 and 4 Hz and have been reported at various hydrocarbon sites worldwide. There are differing views on the mechanisms responsible for these anomalies
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Shortest-path ray tracing on Self-Adapting Random Grids Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-05 Alejandro Quiaro, Mauricio D Sacchi
Summary A new ray-tracing algorithm based on the shortest path method was designed and optimized to model seismic rays. The workflow is based on Dijkstra’s algorithm to find the shortest path iteratively on Self-Adapting Random Grids. These random grids adapt from one iteration to the next, storing in memory those nodes that minimize the travel time in each iteration, consequently automatically densifying
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Understanding earthquake location uncertainties using global sensitivity analysis framework Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-05 Marine Laporte, Jean Letort, Michaël Bertin, Laurent Bollinger
Summary Earthquake hypocenters are routinely obtained by a common inversion problem of P- and S-phase arrivals observed on a seismological network. Improving our understanding of the uncertainties associated with the hypocentral parameters is crucial for reliable seismological analysis, understanding of tectonic processes, and assessing seismic hazards. However, current methods often overlook uncertainties
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Spatial distribution of mid-lower crustal flow in the SE Tibetan Plateau revealed by P-wave velocity and azimuthal anisotropy beneath the Lijiang–Xiaojinhe fault and its vicinity Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-05 Guiju Dong, Shaolin Liu, Kailin Sun, Dinghui Yang, Mengyang Li, Wenshuai Wang, Kai Chang
Summary The Lijiang–Xiaojinhe fault (LXF) and its vicinity are located in the transition zone among the Tibetan Plateau (TP), the South China block and the Indochina block. Researchers believe that this area has acted as a key tectonic zone during the evolution of the TP. Owing to the continuous growth and SE-ward expansion of the TP, the LXF and its vicinity have experienced intense deformation. Although
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Stress Triggering and Future Seismic Hazards Implied by Four Large Earthquakes in the Pamir from 2015 to 2023 Revealed by Sentinel-1 Radar Interferometry Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-05 Zhenjiang Liu, Zhenhong Li, Chen Yu, Xuesong Zhang, Jianbing Peng
Summary The Mw 6.8 Murghob earthquake is the third earthquake in an Mw 6.4+ sequence occurring in the Pamir initiated by the 2015 Sarez Mw 7.2 earthquake. It is of great significance to investigate their interactions and to assess future seismic hazards in the region. In this paper, we use Sentinel-1 radar interferometric data to retrieve coseismic deformation, invert for the slip distributions of
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Towards Limited-Domain Full Waveform Ambient Noise Inversion Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-04 Victor C Tsai, Korbinian Sager, Daniel C Bowden
Summary Ambient noise tomography is a well-established tomographic imaging technique but the effect that spatially variable noise sources have on the measurements remains challenging to account for. Full waveform ambient noise inversion has emerged recently as a promising solution but is computationally challenging since even distant noise sources can have an influence on the inter-station correlation
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The 2020 Mw 7.0 Samos (Eastern Aegean Sea) Earthquake: joint source inversion of multi-type data, and tsunami modeling Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-04 Yu-Sheng Sun, Diego Melgar, Angel Ruiz-Angulo, Athanassios Ganas, Tuncay Taymaz, Brendan Crowell, Xiaohua Xu, Varvara Tsironi, Ilektra Karasante, Seda Yolsal-Çevikbilen, Ceyhun Erman, Tahir Serkan Irmak, Yeşim Çubuk-Sabuncu, Tuna Eken
Summary We present a kinematic slip model and a simulation of the ensuing tsunami for the 2020 Mw 7.0 Néon Karlovásion (Samos, Eastern Aegean Sea) earthquake, generated from a joint inversion of high-rate GNSS, strong ground motion and InSAR data. From the inversion, we find that the source time function has a total duration of ∼20 s with three peaks at ∼4, 7.5 and 15 s corresponding to the development
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Crustal Structure of Borneo, Makassar Strait, and Sulawesi from Ambient Noise Tomography Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-04 N Heryandoko, A D Nugraha, Z Zulfakriza, S Rosalia, T Yudistira, S Rohadi, D Daryono, P Supendi, N Nurpujiono, F Yusuf, F Fauzi, A Lesmana, Y M Husni, B S Prayitno, R Triyono, S P Adi, D Karnawati, T Greenfield, N Rawlinson, S Widiyantoro
Summary Borneo and Sulawesi are two large islands separated by the Makassar Strait that lie within the complex tectonic setting of central Indonesia. The seismic structure beneath this region is poorly understood due to the limited data availability. In this study, we present Rayleigh wave tomography results that illuminate the underlying crustal structure. Group velocity is retrieved from dispersion
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Physical properties variations in a shaly formation across a fault core Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-04 Audrey Bonnelye, Christian David, Jérôme Wassermann, Alexandre Schubnel, Pierre Henry, Yves Guglielmi, Claude Gout, Pierre Dick
Summary Faults in general, and in clay materials in particular, have complex structures that can be linked to both a polyphased tectonic history and to the anisotropic nature of the intact rock. Drilling through faults in shaly materials allows measuring properties such as the structure, mineralogical composition, stress orientation and physical properties. We combine different petrophysical measurements
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Geomechanical modeling of injection-induced seismicity: the case study of the Muara Laboh geothermal plant Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-04 G Gerardi, P Dublanchet, L Jeannin, A Kazantsev, L Duboeuf, I Ramadhan, H Azis, N Ganefianto, I A Nugroho
Summary In this work, we study the induced seismicity recorded during an injection operation at the Muara Laboh geothermal plant (Indonesia). The swarm, consisting of three bursts activating a normal fault zone, is characterized by rapid earthquake (km/day) migration. We use a 2D rate-and-state asperity model to better understand the physical mechanisms controlling the evolution of this induced swarm
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Azimuthal pore pressure response to teleseismic waves: effects of damage and stress anisotropy Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-03 Ivan Panteleev, Vladimir Lyakhovsky, Eyal Shalev
Summary Pore pressure oscillations induced by stress variations including propagating seismic waves from remote earthquakes have been widely observed in various groundwater systems. The monitored pressure change in wells shows significant water-level oscillations to volumetric strain as well as to S and Love waves. Recent observations demonstrated azimuthal dependence of the pore pressure oscillations
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AI based 1D P & S-wave Velocity Models for the Greater Alpine Region from Local Earthquake Data Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-02 Benedikt Braszus, Andreas Rietbrock, Christian Haberland, Trond Ryberg
Summary The recent rapid improvement of machine learning techniques had a large impact on the way seismological data can be processed. During the last years several machine learning algorithms determining seismic onset times have been published facilitating the automatic picking of large data sets. Here we apply the deep neural network PhaseNet to a network of over 900 permanent and temporal broad
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Estimation of rock physics properties via full waveform inversion of vertical seismic profile data recorded by accelerometer and fiberoptic sensors Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-02 Qi Hu, Matthew V Eaid, Kristopher A Innanen, Scott D Keating, Xiaohui Cai
Combining elastic full waveform inversion (FWI) with rock physics holds promise for expanding the application of FWI beyond seismic imaging to predicting and monitoring reservoir properties. Distributed Acoustic Sensing (DAS), a rapidly developing seismic acquisition technology, is being explored for its potential in supporting FWI applications. In this study, we implement a sequential inversion scheme
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Sediment thickness across Australia from passive seismic methods Geophys. J. Int. (IF 2.8) Pub Date : 2024-03-01 Augustin Marignier, Caroline M Eakin, Babak Hejrani, Shubham Agrawal, Rakib Hassan
Summary Around the world the Earth’s crust is blanketed to various extents by sediment. For continental regions, knowledge of the distribution and thickness of sediments is crucial for a wide range of applications including seismic hazard, resource potential, and our ability to constrain the deeper crustal geology. Excellent constraints on the sediment thickness can be obtained from borehole drilling
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Distribution of gas hydrate in fractured reservoirs: implications from anisotropic elastic and electrical numerical simulations Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-29 Shengbiao Liu, Tongcheng Han, Li-Yun Fu
Summary Fractured hydrate-bearing reservoirs are extensively discovered worldwide and show notable anisotropic geophysical properties. Hydrate distribution in fractures significantly affects the anisotropic properties, and hence plays an important role in the accurate assessment of hydrate resources. However, the knowledge about how the hydrate distribution impacts the anisotropic geophysical properties
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Changes in core-mantle boundary heat flux patterns throughout the supercontinent cycle Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-28 Juliane Dannberg, Rene Gassmoeller, Daniele Thallner, Frederick LaCombe, Courtney Sprain
Summary The Earth’s magnetic field is generated by a dynamo in the outer core and is crucial for shielding our planet from harmful radiation. Despite the established importance of the core-mantle boundary heat flux as driver for the dynamo, open questions remain about how heat flux heterogeneities affect the magnetic field. Here, we explore the distribution of core-mantle boundary heat flux on Earth
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Resolving a Ramp-flat Structure from Combined Analysis of Co- and Post-seismic Geodetic Data: an Example of the 2015 Pishan Mw 6.5 Earthquake Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-28 Xiong Zhao, Yangmao Wen, Caijun Xu, Kefeng He, Torsten Dahm
Summary Previous studies have shown that it is difficult to determine whether the 2015 Pishan earthquake occurred on a uniform fault or a ramp-flat fault with variable dip angles due to the similar goodness of data fit to co-seismic and afterslip models on these two fault models. Here, we first present the InSAR deformation obtained from both ascending and descending orbits, covering the coseismic
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Analyzing the impact of SWOT observation errors on marine gravity recovery Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-28 Mingzhi Sun, Wei Feng, Daocheng Yu, Xiaodong Chen, Weixuan Liang, Min Zhong
Summary The wide-swath altimeter satellite Surface Water and Ocean Topography (SWOT) will provide high spatiotemporal resolution sea surface heights (SSHs), which is crucial for studying the impact of observation errors on marine gravity recovery. This study uses simulated SWOT data to derive deflection of the vertical (DOV) and gravity anomalies in the northern South China Sea. We quantified the impact
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Unsupervised clustering of catalog-driven features for characterizing temporal evolution of labquake stress Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-27 Sadegh Karimpouli, Grzegorz Kwiatek, Patricia Martínez-Garzón, Georg Dresen, Marco Bohnhoff
Summary Earthquake forecasting poses significant challenges, especially due to the elusive nature of stress states in fault systems. To tackle this problem, we employ features derived from seismic catalogs obtained from acoustic emission (AE) signals recorded during triaxial stick-slip experiments on natural fractures in three Westerly granite samples. We extracted 47 physically explainable features
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Seismic cycle controlled by subduction geometry: Novel 3D quasi-dynamic model of Central Chile megathrust Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-25 Marco T Herrera, Jorge G F Crempien, José Cembrano, Marcos Moreno
Summary Subduction earthquakes show complex spatial and temporal rupture patterns, exhibiting events of varied sizes, which rupture distinct or overlapping fault segments. Elucidating first-order controlling conditions of rupture segmentation and return periods of large earthquakes is therefore critical for seismic and tsunami hazard estimations. The Chilean subduction zone frequently hosts several
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Transfer learning model for estimating site amplification factors from limited microtremor H/V spectral ratios Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-23 Da Pan, Hiroyuki Miura, Chiman Kwan
Summary Site amplification factors (SAFs) of seismic ground motions are essential in evaluating and estimating seismic hazards. In our previous study, the authors proposed a simple and cost-effective method to estimate a SAF based on a deep neural network (DNN) model and microtremor horizontal-to-vertical spectral ratio (MHVR). Since the previous DNN model was based on the observed SAFs and MHVRs within
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Coseismic slip distribution of the 2023 earthquake doublet in Turkey and Syria from joint inversion of Sentinel-1 and Sentinel-2 data: An iterative modeling method for mapping large earthquake deformation Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-23 Jianlong Chen, Yu Zhou
Summary Interferometric synthetic aperture radar (InSAR) decorrelation that creates great challenges to phase unwrapping has been a critical issue for mapping large earthquake deformation. Some studies have proposed a “remove-and-return model” solution to tackle this problem, but it has not been fully validated yet, and therefore has rarely been applied to real earthquake scenarios. In this study,
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A statistical framework for detection of b-value anomalies in Italy Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-22 Lombardi Anna Maria
Summary This study presents a new robust statistical framework, in which to measure relative differences, or deviations from a hypothetical reference value, of Gutenberg-Richter b-value. Moreover, it applies this method to recent seismicity in Italy, to find possible changes of earthquake magnitude distribution in time and space. The method uses bootstrap techniques, which have no prior assumptions
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Characterisation of train kinematics and source wavelets from near-field seismic data Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-22 Théo Rebert, Thomas Bardainne, Thibaut Allemand, Caifang Cai, Hervé Chauris
Summary Train traffic is a powerful source of seismic waves, with many applications for passive seismic imaging. Seismic signals were recorded a few meters away from the railway track. These records display harmonious waveforms below 15 Hz for trains driving at speeds of around 100 km/h. The sensors record an apparent wavelet emitted by the interaction of the axle on a few of the closest sleepers.
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MUYSC: An end-to-end muography simulation toolbox Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-20 J Peña-Rodríguez, J Jaimes-Teherán, K Dlaikan-Castillo, L A Núñez
Summary Muography is an imaging technique that relies on the attenuation of the muon flux traversing geological or anthropogenic structures. Several simulation frameworks help to perform muography studies by combining specialised codes: for muon generation through muon transport to muon detector performance. This methodology is precise but requires significant computational resources and time. We present
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High-resolution source imaging and moment tensor estimation of acoustic emissions during brittle creep of basalt undergoing carbonation Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-19 Tong Bai, Tiange Xing, Matěj Peč, Nori Nakata
Summary As the high-frequency analog to field-scale earthquakes, acoustic emissions (AEs) provide a valuable complement to study rock deformation mechanisms. During the load-stepping creep experiments with CO2-saturated water injection into a basaltic sample from Carbfix site in Iceland, 8791 AE events are detected by at least one of the seven piezoelectric sensors. Here, we apply a cross-correlation-based
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Deep investigation of muography in discovering geological structures in mineral exploration: a case study of Zaozigou gold mine Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-17 Guorui Liu, Kaiqiang Yao, Feiyun Niu, Zhuodai Li, Heng Tian, Jiangkun Li, Xujia Luo, Long Jin, Jinlei Gao, Jian Rong, Zhiqiang Fu, Youxin Kang, Weixiong Zhang, Shuhong Ding, Yuxi Wang, Junjie Zeng, Xiaogang Luo, Xiangsheng Tian, Wenquan Shi, Jiqiu Hu, Zhiping Zhang, Minghai Yu, Feng Wu, Jingjing Chen, Juntao Liu, Zhiyi Liu
Summary Muography is a promising and rapidly developing physical prospecting technique based on the attenuation of muon flux. The feasibility and potential of applying muography to mining were presented in a small number of previous case studies. In this work, we aimed to address three challenges that limit the applicability and efficiency of muography in mineral exploration: (1) application to low-density-contrast
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Subsurface anatomy of the Irazú-Turrialba volcanic complex, inferred from the integration of local and ambient seismic tomographic methods Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-17 E A Jiwani-Brown, I Koulakov, F Muñoz-Burbano, J F Pacheco, M M Mora, G Savard, M Lupi
Summary Irazú and Turrialba are a twin volcanic complex that marks a distinct stop in volcanism along the Central America volcanic arc. We present a new travel-time velocity model of the crust beneath Irazú and Turrialba volcanoes, Costa Rica, and interpret it considering the results of previous ambient noise tomographic inversions. Data were acquired by a temporary seismic network during a period
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Quantifying the characteristics of magnetic oil-water contacts in mature hydrocarbon reservoirs and their capacity for understanding hydrocarbon remigration Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-16 Jack N Turney, Adrian R Muxworthy, Michael J E Sims, Dominik Weiss, Alastair Fraser
Summary Increasing magnetisation within mature hydrocarbon reservoirs provides a new technique in identifying oil-water contacts (OWCs) in cored wells with the potential to assess yield thereby reducing the need for further exploration. Authigenic precipitation of magnetic minerals at OWCs may also help locate paleocontacts (PCs), where structural changes to the petroleum system have caused hydrocarbon
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Mesh size effect on finite source inversion with 3D finite element modeling Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-15 Minsu Kim, Byung-Dal So, SatByul Kim, Taehwan Jo, Sung-Joon Chang
Summary Three-dimensional finite element models, which can handle the stress perturbations caused by subsurface mechanical heterogeneities and fault interactions, have been combined with the finite source inversion to estimate the coseismic slip distribution over the fault plane. However, the mesh grid for discretizing the governing equations in the finite element model significantly affects the numerical
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Efficient similar waveform search using short binary codes obtained through a deep hashing technique Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-15 Makoto Naoi, Shiro Hirano
Summary A similar waveform search plays a crucial role in seismology for detecting seismic events, such as small earthquakes and low-frequency events. However, the high computational costs associated with waveform cross-correlation calculations represent bottlenecks during the analysis of long, continuous records obtained from numerous stations. In this study, we developed a deep-learning network to
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Inverse modelling and classification of magnetic responses to improve marine unexploded ordnance rationalization Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-12 Jack Brighouse, Martin Wood, Eoin McGregor, Andrew Kirkland, David Sinclair, Dorthe Reng Erbs-Hansen, Simon Hviid
SUMMARY Unexploded ordnance (UXO), often deployed in WWI and WWII, are still present on the seabed posing a risk to seabed construction. UXO surveys identify potential UXO targets which are then investigated and removed where necessary; however, approximately 96 per cent of targets investigated on projects included in this study were non-UXO (false positives). Here we investigate methods of improving
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Near-source effects on DAS recording: implications for tap tests Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-10 B L N Kennett, V H Lai, M S Miller, D Bowden, A Fichtner
Summary In the immediate vicinity of a source there are strong gradients in the seismic wavefield that are tamed and modified in DAS recording due to combined effects of gauge-length averaging and local stacking on the local strain field. Close to a source broadside propagation effects are significant, and produce a characteristic impact on the local DAS channels. In the presence of topography, of
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Remagnetization of the Upper Permian–Lower Triassic limestones in the western Lhasa Terrane and its tectonic implications Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-09 Weiwei Bian, Xianwei Jiao, Suo Wang, Jiacheng Liang, Jiahui Ma, Jikai Ding, Hanqing Zhao, Tianshui Yang, Shihong Zhang, Huaichun Wu, Haiyan Li, Chenglong Deng
Summary The drift history of the Lhasa terrane plays an essential role in understanding the tectonic evolution of the Bangong-Nujiang Tethyan Ocean and the Neo-Tethyan Ocean, as well as the evolutionary history of the Tibetan Plateau. Here, a combined rock magnetic, petrographic, and palaeomagnetic study is performed on the Upper Permian–Lower Triassic limestones (∼259–251 Ma) in the western Lhasa
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Improved ERT imaging with three-dimensional surface-to-horizontal borehole configurations: relevance to dense non-aqueous phase liquids Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-08 Maxwell Servos, Christopher Power
Summary Accurate characterization and monitoring strategies are essential for designing and implementing remedial programs for sites polluted with dense non-aqueous phase liquids (DNAPLs). Electrical resistivity tomography (ERT) is a widely used geophysical technique for mapping subsurface features and processes of interest and exhibits desirable characteristics for DNAPL sites due to its ability to
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Seismic moment tensor classification using elliptical distribution functions on the hypersphere Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-07 Mark J Hoggard, Janice L Scealy, Brent G Delbridge
SUMMARY Discrimination of underground explosions from naturally occurring earthquakes and other anthropogenic sources is one of the fundamental challenges of nuclear explosion monitoring. In an operational setting, the number of events that can be thoroughly investigated by analysts is limited by available resources. The capability to rapidly screen out events that can be robustly identified as not
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Deep Attributes: Innovative LSTM-based seismic attributes Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-06 G Roncoroni, E Forte, M Pipan
Summary Seismic attributes are derived measures from seismic data that help characterize subsurface geological features and enhance the interpretation of subsurface structures: we propose to exploit the hidden layers of Long-Short Time Memory neural network predictions as possible new reflection seismic attributes. The idea is based on the inference process of a neural network, which in its hidden
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Toroidal mantle flow beneath the NE termination of the Kuril-Kamchatka subduction zone from seismic anisotropy Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-03 Ayoub Kaviani, Georg Rümpker, Christoph Sens-Schönfelder, Abolfazl Komeazi, Nikolai Shapiro
Summary This study presents the findings of a splitting analysis conducted on core-refracted teleseismic shear waves (SKS, SKKS, and PKS, called together as XKS) and local shear waves, obtained from a dense seismological network spanning the Kamchatka Peninsula. The objective of the study is to examine the pattern of mantle flow beneath the study area through the investigation of seismic anisotropy
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A tale of two faults: Statistical reconstruction of the 1820 Flores Sea earthquake using tsunami observations alone Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-03 T Paskett, J P Whitehead, R A Harris, C Ashcraft, J A Krometis, I Sorensen, R Wonnacott
Summary Using a Bayesian approach we compare anecdotal tsunami runup observations from the 29 December 1820 Flores Sea earthquake with close to 200,000 tsunami simulations to determine the most probable earthquake parameters causing the tsunami. Using a dual hypothesis of the source earthquake either originating from the Flores Thrust or the Walanae/Selayar Fault, we found that neither source perfectly
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A probabilistic solution to geophysical inverse problems in complex variables and its application to complex resistivity imaging Geophys. J. Int. (IF 2.8) Pub Date : 2024-02-02 Joost Hase, Maximilian Weigand, Andreas Kemna
We introduce a novel probabilistic framework for the solution of non-linear geophysical inverse problems in complex variables. By using complex probability distributions, this approach can simultaneously account for individual errors of real and imaginary data parts, independently regularize real and imaginary parts of the complex model, and still take into account cross-sensitivities resulting from
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Applying the Beidou Navigation Satellite System in the acquisition of the co-seismic deformation and the high-frequency dynamic displacement of the 2021 MW7.4 Maduo earthquake Geophys. J. Int. (IF 2.8) Pub Date : 2024-01-30 Yuebing Wang, Weijun Gan, Hongbo Shi, Yu Li, Xinzhao You
Summary This study acquires the co-seismic deformation field of the MW7.4 earthquake that occurred in Maduo, China, on May 22, 2021, based on the BeiDou Navigation Satellite System (BDS), and the comparison with the results obtained by the Global Positioning System (GPS) reveals that the two systems are certain differences in their ability to acquire the horizontal co-seismic deformation field. The
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Topography effect on seismic waveform tomography: a quantitative study Geophys. J. Int. (IF 2.8) Pub Date : 2024-01-26 Kaiyue Zheng, Yi Wang, Li Zhao
Summary In seismic tomography practices the Earth's surface is sometimes assumed to be either spherical or flat for convenience in forward modeling calculations. The effect of irregular surface topography on seismic wave propagation is thus ignored, resulting in biases in the phases and amplitudes of synthetic seismograms, which contribute to the residuals that are mapped into velocity structures in
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Artificial age-independent seismic anisotropy, slab thickening and shallowing due to limited resolving power of (an)isotropic tomography Geophys. J. Int. (IF 2.8) Pub Date : 2024-01-25 F Rappisi, M Witek, M Faccenda, A M G Ferreira, S-J Chang
Summary Seismic anisotropy is key to constrain mantle flow, but it is challenging to image and interpret it. Existing large-scale tomography models of seismic anisotropy typically show large discrepancies, which can lead to completely distinct geodynamical interpretations. To better quantify the robustness of anisotropy tomography, we create a 2-D ridge-to-slab geodynamic model and compute the associated
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Low-strength shear zone in the western Makran subduction zone, southeastern Iran: insights from a receiver functions analysis Geophys. J. Int. (IF 2.8) Pub Date : 2024-01-25 S Abbasi, K Motaghi, F P Lucente, I Bianchi
Summary To understand the seismic hazard of a subduction zone, it is necessary to know the geometry, location, and mechanical characteristics of the interplate boundary below which an oceanic plate is thrust downward. By considering the azimuthal dependence of converted P-to-S (Ps) amplitudes in receiver functions (RFs), we have detected the interplate boundary in the Makran subduction zone, revealing
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Multifidelity adaptive sequential Monte Carlo for geophysical inversion Geophys. J. Int. (IF 2.8) Pub Date : 2024-01-25 M Amaya, G Meles, S Marelli, N Linde
Summary In the context of Bayesian inversion, we consider sequential Monte Carlo (SMC) methods that provide an approximation of the posterior probability density function and the evidence (marginal likelihood). These particle approaches build a sequence of importance sampling steps between gradually-tempered distributions evolving from the prior to the posterior PDF. To automate the definition of the
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Spatial variation in shallow slow earthquake activity in Hyuga-nada, southwest Japan Geophys. J. Int. (IF 2.8) Pub Date : 2024-01-25 Satoru Baba, Shunsuke Takemura, Kazushige Obara, Akiko Takeo, Yusuke Yamashita, Masanao Shinohara
Summary Hyuga-nada, off the Pacific coast of Kyushu along the Nankai Trough in southwest Japan, is one of the most active slow earthquake regions around Japan. We estimated the energies of shallow tremors and moments of shallow very low frequency earthquakes (VLFEs) in Hyuga-nada using data from a permanent onshore broadband network and temporary ocean bottom seismometer observations. The energies