Journal of Geophysical Research: Solid Earth最新文献

{"title":"The Role of Grain Size on Shear Localization Illuminated by Acoustic Emissions","authors":"N. Casas,&nbsp;C. Giorgetti,&nbsp;F. Pignalberi,&nbsp;M. M. Scuderi","doi":"10.1029/2024JB030448","DOIUrl":"https://doi.org/10.1029/2024JB030448","url":null,"abstract":"<p>Shear localization within the fault core, as evidenced by grain comminution in fault gouge, plays a crucial role in the initiation of frictional instabilities. To upscale the physics of shear localization and understand the influence of grain size, it is essential to identify the governing physical parameters and micro-mechanisms. In this study, we conducted double-direct shear experiments on quartz fault gouges with varying initial grain sizes (coarse, small, and bi-disperse mixtures) under constant normal stress and shearing velocity, while continuously monitoring Acoustic Emissions (AE). Microstructural analyses were performed on the deformed samples to complement the mechanical and AE data. Our results reveal that, while the initial grain size and distribution do not substantially alter the steady-state friction coefficient, they significantly influence the early stages of frictional evolution leading to a steady state, which is reflected in a different rate and amplitude of AEs. Specifically, coarse grains and bi-disperse mixtures exhibit strain-hardening behavior before reaching steady-state friction, whereas fine grains show strain-weakening behavior. Microstructural observations further indicate that bi-disperse mixtures retard the localization of deformation with increasing fault displacement. The AE data shows a strong dependence on both the average grain size and the evolving state of the gouge layer. Notably, there is a direct correlation between b-value evolution and the average grain size within the gouge. These findings suggest that variations in the characteristics of AE are indicative of distinct micro-mechanisms active during different stages of shear localization, which cannot be fully captured by mechanical data and microstructural analysis alone.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030448","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thank You to Our 2024 Reviewers","authors":"Alexandre Schubnel,&nbsp;Rachel Abercrombie,&nbsp;Mark D. Behn,&nbsp;Yves Bernabé,&nbsp;Mark Dekkers,&nbsp;Susanna Ebmeier,&nbsp;Anke Friedrich,&nbsp;Shin-Chan Han,&nbsp;Satoshi Ide,&nbsp;Fenglin Niu,&nbsp;Douglas R. Schmitt,&nbsp;Jun Tsuchiya","doi":"10.1029/2025JB031548","DOIUrl":"10.1029/2025JB031548","url":null,"abstract":"<p>The entire editorial board of the <i>Journal of Geophysical Research-Solid Earth</i> would like to sincerely thank all our colleagues who reviewed manuscripts for us in 2024. The hours they spent reading in order to provide insightful comments on manuscripts not only help improve the quality of these manuscripts but also ensure the scientific rigor of our reviewing process and eventually, of the research published in the field of Solid Earth Geophysics by our journal. With the advent of open science and AGU's data policy, the reviewing process now also encompasses checking the accessibility and availability of data and developed software. This is a key objective of AGU's FAIR (Findable, Accessible, Interoperable and Reusable) (FAIR) policy, for which many reviewers have provided suggestions that helped to improve the data presentation and availability, and which also fed the editorial board's reflection on the matter. Of course, we particularly appreciate timely reviews, particularly in light of the growing demands imposed by the increase of manuscripts submitted to <i>Journal of Geophysical Research-Solid Earth</i>. We received 1,999 submissions in 2024, and 1,628 reviewers contributed to their evaluation by providing 2,534 reviews in total. We are deeply thankful for all of their contributions.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB031548","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ambient Noise Array Tomography Using Regionalized Phase Velocities From Array-Based Methods","authors":"Kaifeng Zhao,&nbsp;Yingjie Yang,&nbsp;Yinhe Luo,&nbsp;Hao Jin,&nbsp;Chengxin Jiang","doi":"10.1029/2024JB030280","DOIUrl":"https://doi.org/10.1029/2024JB030280","url":null,"abstract":"<p>With the advancement of dense seismic arrays, array-processing methods for ambient noise data have become highly effective in extracting high-quality broadband surface wave dispersion curves from ambient noise. Recent advancements in array data processing methods have enabled the extraction of multimode dispersion curves, offering improved constraints on deep Earth structures. However, these array-based methods often produce regionalized dispersion curves, and conventional phase velocity maps constructed by interpolating these dispersion curves typically have limited resolution, and display smooth images of phase velocities. In this study, we develop an array tomography method aimed at improving the resolution of ambient noise tomography by utilizing dispersion curves extracted through array-based data processing. To demonstrate the effectiveness of our method in enhancing tomography resolution, we construct fundamental-mode 2-D Rayleigh wave phase velocity maps by applying our approach to regionalized dispersion curves obtained from array-based methods in the western United States. By comparing our tomographic results with those from conventional array-based methods, we show that our method can produce more accurate and higher-resolution phase velocity maps. Additionally, our approach is versatile and can be applied to construct high-resolution 1-D and 2-D velocity structures using regionalized phase velocities obtained from various other array-based data processing methods.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143690274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic Imaging of the Salt Lake Basin Using Joint Inversion of Receiver Functions and Rayleigh Wave Data","authors":"HyeJeong Kim,&nbsp;Fan-Chi Lin,&nbsp;James C. Pechmann,&nbsp;Christian L. Hardwick,&nbsp;Adam P. McKean","doi":"10.1029/2024JB030927","DOIUrl":"https://doi.org/10.1029/2024JB030927","url":null,"abstract":"<p>This study presents a new velocity model for the Salt Lake basin (SLB) in Utah, determined using data from permanent and temporary seismic stations located on top of the basin in the Salt Lake Valley (SLV) and nearby. A three-dimensional (3D) velocity model for the SLB is needed for accurate predictions of future damaging earthquake ground shaking in the heavily urbanized SLV, including Salt Lake City. The SLB part of the Wasatch Front community velocity model (WFCVM) currently serves this purpose. However, the current WFCVM is based primarily on gravity and borehole data with relatively few seismic constraints below depths of 100 m. In this study we use the first peak of SLV receiver functions (RFs), which is sensitive to a strong impedance contrast at the base of a semi-consolidated sediment layer. We jointly invert the RF waveform with Rayleigh wave ellipticity (H/V) and phase velocity measurements using the Markov chain Monte Carlo approach. Our new velocity model shows a greater combined thickness of unconsolidated and semi-consolidated sediments, compared to the WFCVM, in the northeastern SLB between the west-dipping East Bench fault section of the Wasatch fault and the antithetic West Valley fault zone to the west. We show that the new seismic velocity model explains the gravity patterns in the valley. The new velocity model from this study provides a basis for revising the SLB model in the WFCVM.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030927","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143690276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Systematic Differences in Energy Radiation Processes Between Regular and Intraplate Low-Frequency Earthquakes Around the Focal Area of the 2008 \u0000 \u0000 \u0000 \u0000 M\u0000 w\u0000 \u0000 \u0000 ${boldsymbol{M}}_{boldsymbol{w}}$\u0000 6.9 Iwate-Miyagi, Japan, Earthquake","authors":"Masaki Orimo,&nbsp;Keisuke Yoshida,&nbsp;Toru Matsuzawa,&nbsp;Taka'aki Taira,&nbsp;Kentaro Emoto,&nbsp;Akira Hasegawa","doi":"10.1029/2024JB030750","DOIUrl":"10.1029/2024JB030750","url":null,"abstract":"&lt;p&gt;Many unknowns exist regarding the energy radiation processes of intraplate low-frequency earthquakes (LFEs), which are frequently observed beneath volcanoes. To evaluate their energy radiation characteristics, we estimated scaled energy (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;e&lt;/mi&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${e}_{R}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) for LFEs and regular earthquakes around the focal area of the 2008 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;M&lt;/mi&gt;\u0000 &lt;mi&gt;w&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${M}_{w}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 6.9 Iwate-Miyagi, Japan, earthquake. Their source spectra were first obtained by correcting for the site and path effects from direct S-waves. We then estimated the radiated energy and seismic moment and obtained the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;e&lt;/mi&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${e}_{R}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; for the 1,421 regular earthquakes, 62 deep LFEs, and 46 shallow LFEs. The &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;e&lt;/mi&gt;\u0000 &lt;mi&gt;R&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${e}_{R}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; for the regular earthquakes is in the order of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mn&gt;10&lt;/mn&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;5&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${10}^{-5}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; to &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mn&gt;10&lt;/mn&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;mn&gt;4&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${10}^{-4}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, typical for crustal earthquakes and tends to be smaller near volcanoes and the shallow LFEs. In contrast, the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;e&lt;/mi&gt;\u0000 ","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030750","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trans-Crustal Geophysical Responses Beneath the Supergiant Timmins-Porcupine Orogenic Gold Camp, Canada","authors":"A. Q. Adetunji,&nbsp;I. J. Ferguson,&nbsp;J. M. Simmons,&nbsp;C. Ma,&nbsp;S. Cheraghi,&nbsp;D. B. Snyder,&nbsp;J. A. Ayer","doi":"10.1029/2024JB028839","DOIUrl":"10.1029/2024JB028839","url":null,"abstract":"<p>A new 80-site magnetotelluric (MT) survey, integrated with reprocessed seismic reflection profiles, across the supergiant Timmins-Porcupine gold camp of the Abitibi greenstone belt (AGB) was conducted to investigate the architecture of crustal-scale structures. Resistivity sections derived from 3-D MT inversions reveal a significant 600 S conductor north of the Porcupine-Destor fault zone at 3–5 km depth striking east-west parallel to the Pipestone fault zone. It is attributed to a deeply buried &gt;2687 Ma graphitic argillaceous unit at the base of Porcupine assemblage. A second conductor at 8–10 km depth strikes northwest-southeast parallel to the Buskegau River fault. The margin of this conductor correlates spatially with lateral breaks in seismic reflectors and velocity models in the upper, middle, and lower crust, and adds to evidence of a crustal-scale suture which also resulted in imbrication of &lt;2698 Ma metasedimentary rocks onto the southern AGB. Enhanced conductivity and spatially complex electrical structure of the crust to the north of the Porcupine-Destor fault zone reflect the asymmetric distribution of metasedimentary packages, second- and third-order bounding structures, and gold mineralization. The MT resistivity models also resolve an upper crustal conductor located 10 km south of the surface trace of the Porcupine-Destor fault zone, providing support for a south-dipping crustal fault. The Timmins results suggest middle crustal signatures of the extensional stage of the fault system have been overprinted by orogen-parallel ductile flow at ∼2660–2590 Ma and narrow (2–5 km wide) breaks in seismic reflectors are more likely associated with late strike-slip deformation.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB028839","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Paleomagnetic Constraints on the Eruption Timing, Stratigraphy, and Post-Emplacement Deformation of the Picture Gorge Basalt Within the Columbia River Basalt Group","authors":"A. F. Pivarunas,&nbsp;M. S. Avery,&nbsp;J. T. Hagstrum,&nbsp;S. E. K. Bennett,&nbsp;A. T. Calvert","doi":"10.1029/2024JB030728","DOIUrl":"10.1029/2024JB030728","url":null,"abstract":"<p>The Picture Gorge Basalt (PGB) is part of the Miocene Columbia River Basalt Group (CRBG). The PGB, which outcrops in eastern Oregon, is considered coincident in time with the voluminous Grande Ronde Basalt. New radiometric ages have expanded the age-range of the PGB, suggesting it began erupting prior to the Steens Basalt to its south and continued until after cessation of the Grande Ronde Basalt eruptions, an interval of 1.5 Ma. However, the existing paleomagnetism of the PGB implies this eruption timeline is an overestimate. To reconcile the radiometric and paleomagnetic timescales for the PGB, we conducted a paleomagnetic study on sections of the PGB to construct a detailed, high-quality magnetostratigraphy. Our data indicate the stratigraphically lowest lava flows in the PGB are of reversed polarity, revealing a new paleomagnetic transition with the PGB and a reversed (R)–normal (N)–reversed (R) sequence. This suggests one of two timeline possibilities for PGB volcanism: (a) eruptions began and during through CRBG polarity chrons R0–N0–R1, penecontemporaneous with Steens Basalt, or (b) eruptions began and persisted during CRBG polarity chrons R1–N1–R2. Our work supports a longer interval of PGB volcanism than was suggested by previous paleomagnetic data but is at odds with the suggestion that PGB eruptions lasted through the entire main CRBG. We favor a scenario wherein PGB eruptions begin with R0 and continue into the R1 paleomagnetic interval. The paleomagnetic results also record a ∼18° vertical-axis rotation of east-central Oregon after ∼16 Ma with respect to stable North America.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"b-Bayesian: The Full Probabilistic Estimate of b-Value Temporal Variations for Non-Truncated Catalogs","authors":"M. Laporte,&nbsp;S. Durand,&nbsp;T. Bodin,&nbsp;B. Gardonio,&nbsp;D. Marsan","doi":"10.1029/2024JB029973","DOIUrl":"10.1029/2024JB029973","url":null,"abstract":"&lt;p&gt;The frequency/magnitude distribution of earthquakes can be approximated by an exponential law whose exponent (the so-called &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;mi&gt;value&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${b}_{mathit{value}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) is routinely used for probabilistic seismic hazard assessment. The &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;v&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;l&lt;/mi&gt;\u0000 &lt;mi&gt;u&lt;/mi&gt;\u0000 &lt;mi&gt;e&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${b}_{value}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; is commonly measured using Aki's maximum likelihood estimation, although biases can arise from the choice of completeness magnitude (i.e., the magnitude below which the exponential law is no longer valid). In this work, we introduce the b-Bayesian method, where the full frequency-magnitude distribution of earthquakes is modeled by the product of an exponential law and a detection law. The detection law is characterized by two parameters, which we jointly estimate with the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;mi&gt;value&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${b}_{mathit{value}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; within a Bayesian framework. All available data are used to recover the joint probability distribution. The b-Bayesian approach recovers temporal variations of the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;mi&gt;value&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${b}_{mathit{value}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and the detectability using a transdimensional Markov-chain Monte Carlo algorithm to explore numerous configurations of their time variations. An application to a seismic catalog of far-western Nepal shows that detectability decreases significantly during the monsoon period, while the &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mi&gt;b&lt;/mi&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;v&lt;/mi&gt;\u0000 &lt;mi&gt;a&lt;/mi&gt;\u0000 &lt;mi&gt;l&lt;/mi&gt;\u0000 &lt;mi&gt;u&lt;/mi&gt;\u0000 &lt;mi&gt;e&lt;/","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029973","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic Anisotropy Variations in the Eastern Mediterranean Sea Region Revealed by Splitting Intensity Tomography: Implications on Mantle Dynamics","authors":"Ceyhun Erman,&nbsp;Seda Yolsal-Çevikbilen,&nbsp;Tuna Eken,&nbsp;Zhouchuan Huang,&nbsp;Tuncay Taymaz","doi":"10.1029/2024JB030331","DOIUrl":"10.1029/2024JB030331","url":null,"abstract":"<p>Reliable knowledge of seismic anisotropy in the mantle can provide invaluable insights into complex tectonics and geodynamics in Anatolia controlled by intricate plate interactions across the region. However, the 3D variations in seismic anisotropy within the crust and upper mantle beneath this area remain poorly constrained. In the present study, we performed splitting intensity (SI) tomography technique, using over 25,000 SI measurements from SKS/SKKS waves recorded at 690 seismic stations, to map lateral and vertical variation of anisotropy that is essential for accurate geodynamic interpretations for Eastern Mediterranean. Our tomographic images show large-scale mantle flow at asthenospheric depths, oriented in east-west and northeast-southwest directions. This flow pattern can be attributed to basal drag forces, which play an important role in driving the westward motion of the Anatolian plate. The strong azimuthal anisotropy in the back-arc region of the Hellenic subduction zone, with trench-perpendicular orientation, highlights the significant impact of trench retreat and rollback of the African lithosphere on deformations in the mantle lithosphere and asthenosphere beneath the Aegean region and western Türkiye. The observed weak azimuthal anisotropy, on the other hand, is largely identified across various depths beneath Quaternary volcanoes in the Central and East Anatolian Volcanic Provinces and along the Cyprus subducting slab in the upper mantle. Our numerical tests prove that these weak anomalies may result from plunging/vertical anisotropy associated with upwelling and/or downwelling mantle in central and eastern Anatolia.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030331","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Permeability Anisotropy in Brittle Carbonate Fault Rocks","authors":"E. A. H. Michie,&nbsp;I. Kaminskaite-Baranauskiene","doi":"10.1029/2024JB028763","DOIUrl":"10.1029/2024JB028763","url":null,"abstract":"<p>Permeability anisotropy of fault rocks has been documented in crystalline and clastic lithologies, but rarely within carbonates. In this contribution, we investigate how a permeability anisotropy may develop within carbonate fault rocks, including deformation bands, for the purpose of improving understanding of fluid flow. A total of 43 oriented fault rock samples plugged in three orthogonal directions were taken from eight faults in differing carbonate lithofacies. The permeability was measured, with the goal of assessing if and to what extent a permeability anisotropy may develop. Key factors controlling the formation of anisotropy in these rocks were analyzed by combining petrophysical and microstructural data. All samples showed some degree of anisotropy. However, a consistent major permeability anisotropy (up to five orders of magnitude) only occurred when the same or similar lithofacies were juxtaposed, where the lowest permeability was recorded normal to fault strike in 75% of the samples. Differences occurred in the highest permeability direction dependent on lithofacies. In deformation bands within high porosity grainstones, the highest permeability was inferred to be at a low angle to σ_1, created by grain and pore alignment in the direction of transport. The highest permeability in faults cutting recrystallized carbonates varied from sub-parallel to σ₁, to sub-parallel to σ₂, owing to variations in Riedel shears and fracture orientation during multiple reactivation episodes. Predicting the permeability of a fault zone, including any directional permeability, is key for improved modeling of fluid flow pathways around faults in the subsurface.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB028763","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143666502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}