Journal of Geophysical Research: Solid Earth最新文献

{"title":"Fault Gouge Failure Induced by Fluid Injection: Hysteresis, Delay and Shear-Strengthening","authors":"Pritom Sarma,&nbsp;Einat Aharonov,&nbsp;Renaud Toussaint,&nbsp;Stanislav Parez","doi":"10.1029/2024JB030768","DOIUrl":"https://doi.org/10.1029/2024JB030768","url":null,"abstract":"<p>Natural faults often contain a fluid-saturated, granular fault-gouge layer, whose failure and sliding processes play a central role in earthquake dynamics. Using a two-dimensional discrete element model coupled with fluid dynamics, we simulate a fluid-saturated granular layer, where fluid pressure is incrementally raised. At a critical fluid pressure level, the layer fails and begins to accelerate. When we gradually reduce fluid pressure, a distinct behavior emerges: slip-rate decreases linearly until the layer halts at a fluid pressure level below that required to initiate failure. During this pressure cycle the system exhibits (a) velocity-strengthening friction and (b) frictional hysteresis. These behaviors, well established in dry granular media, are shown to extend here to shear of dense fluid-saturated granular layers. Additionally, we observe a delay between fluid pressure increase and failure, associated with pre-failure dilative strain and “dilational-hardening.” During this delay period, small, arrested slip events dilate the layer in preparation for full-scale failure. Our findings may explain (a) fault motion that continues even after fluid pressure returns to pre-injection levels, and (b) delayed failure in fluid-injection experiments, and (c) pre-failure arrested slip events observed prior to earthquakes.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030768","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144220269","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":"Evolving Sediment Structure and Lithospheric Architecture Across the Indo-Burman Forearc Margin From the Joint Inversion of Surface- and Scattered-Wave Seismic Constraints","authors":"Christopher J. W. Carchedi,&nbsp;James B. Gaherty,&nbsp;Joseph S. Byrnes,&nbsp;Stéphane Rondenay,&nbsp;Michael S. Steckler,&nbsp;Rasheed Ajala,&nbsp;Patricia Persaud,&nbsp;Eric A. Sandvol,&nbsp;Md. Samiul Alim,&nbsp;Sanju Singha,&nbsp;Syed Humayun Akhter","doi":"10.1029/2024JB030050","DOIUrl":"10.1029/2024JB030050","url":null,"abstract":"<p>The Indo-Burman subduction zone represents a global endmember for extreme sediment accretion and is a region characterized by ambiguous tectonic structure. The recent collection of broadband seismic data across the Indo-Burman accretionary margin as part of the Bangladesh-India-Myanmar Array (BIMA) experiment provides an opportunity to investigate the subsurface velocity structure across the incoming plate of an endmember subduction system. We construct a three-dimensional model for seismic shear velocity using a joint inversion of surface- and scattered-wave constraints. Rayleigh-wave phase velocities measured from ambient-noise (12–25 s) and teleseismic earthquakes (20–80 s) constrain absolute shear velocities, while we constrain the locations of and relative contrasts across significant discontinuities in the subsurface using observations from scattered-wave imaging. From the resulting inversion, we observe two model classes that characterize the evolution of consolidation within the markedly slow uppermost sediments and metasediments along a predominantly southwest-to-northeast trend. We interpret variations in deeper seismic structure under two proposed scenarios: (a) a Moho of ∼21–26 km depth underlying a package of metasediments and a thinned basement component, with a slow mantle lithosphere (4.2 km/s) that may contain retained melt from the onset of India-Antarctica seafloor spreading; or (b) a Moho of ∼51–59 km depth underlying a package of metasediments, basement, and a thick slug of mafic material, which may correspond to significant Kerguelen-plume-related underplating. By combining constraints from highly resolved phase-velocity estimates and scattered-wave images, we successfully characterize the lateral transitions across the Indo-Burman forearc margin.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030050","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144219462","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":"Plate-Scale Strike-Slip Fault System in the Barbados Accretionary Wedge of the Lesser Antilles Subduction Zone","authors":"Gaëlle Bénâtre,&nbsp;Nathalie Feuillet,&nbsp;Hélène Carton,&nbsp;Eric Jacques,&nbsp;Thibaud Pichot,&nbsp;Frédérique Leclerc,&nbsp;Christine Deplus","doi":"10.1029/2024JB030059","DOIUrl":"10.1029/2024JB030059","url":null,"abstract":"<p>Fault systems of various geometries develop into accretionary wedges to accommodate slip partitioning of plate convergence in oblique settings. However, how they form, evolve and contribute to the segmentation of the megathrust is still poorly understood. The Barbados accretionary wedge, which results from the subduction of the American plates beneath the Caribbean Plate at 2 cm/yr in a southwesterly direction, is one of the largest on Earth. Here we present a comprehensive morphotectonic study of this wedge based on a new marine geophysical data set acquired during the recent CASEIS marine experiment combined with legacy data sets. From a joint analysis of high-resolution bathymetry and seismic reflection profiles, we characterize a regional-scale left-lateral strike-slip fault system in the wedge, which began to form in Pliocene times and is still active today. It may relay, via a diffuse complex deformation system, to the Bunce left-lateral strike-slip fault in the north and may join the conjugate Kitridge right-lateral fault to the south. Both Bunce and Kitridge faults are themselves linked via relay zones to the main strike-slip fault systems bounding the Caribbean plate. They likely developed along the toe of the backstop and may mark a segmentation of the Lesser Antilles megathrust. The main segment of this system is the newly identified ∼580-km-long Seraphine fault, which is long enough to rupture during magnitude class 8 earthquakes. The kinematics of the entire fault system is incompatible with present-day NE-SW compression inferred at the Caribbean/American plate boundary and raises questions about the current geodynamics of the region.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030059","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144211277","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":"Thermal Pressurization in Rough Faults: Implications for Frictional Melting and Rupture Dynamics","authors":"Nir Z. Badt,&nbsp;Yuval Tal","doi":"10.1029/2024JB030472","DOIUrl":"https://doi.org/10.1029/2024JB030472","url":null,"abstract":"&lt;p&gt;Thermal pressurization (TP) is widely accepted as one of the primary dynamic frictional weakening mechanisms during earthquakes. However, most studies, whether experimental or numerical, have focused on the effects of TP on planar faults, while natural fault surfaces typically exhibit a fractal rough geometry. In this study, we numerically examine how roughness influences the fault thermal and mechanical evolution during coseismic slip. We control roughness using the root mean square prefactor &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;r&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${b}_{r}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, testing faults with varying roughness levels, from a planar fault (&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;r&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${b}_{r}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; = 0) to a rough fault (&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;r&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${b}_{r}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; = 0.008), for two hydraulic diffusivities, representing intact (10&lt;sup&gt;−5&lt;/sup&gt; m&lt;sup&gt;2&lt;/sup&gt;/s) and damaged (10&lt;sup&gt;−4&lt;/sup&gt; m&lt;sup&gt;2&lt;/sup&gt;/s) rocks. Our findings indicate that the average temperature, shear stress drop, and effective normal stress are similar for rough and planar faults. However, while TP effectively buffers the average temperature rise, isolated patches of frictional melts form during coseismic slip at regions of high normal stress on rough faults, with their number and size increasing with &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;r&lt;/mi&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${b}_{r}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. For the rough faults, an increase in hydraulic diffusivity can lead to a transition from a crack to a pulse-like rupture style. Additionally, we investigate the effects of roughness on TP with different shear layer half-widths (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;w&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $w$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;). We observe that faults with &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;w&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $w$","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030472","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144197501","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":"Detection of Lowermost Mantle Heterogeneity Using Seismic Migration of Diffracted S-Waves","authors":"Jonathan Wolf,&nbsp;Edward Garnero,&nbsp;Benjamin Schwarz,&nbsp;Kuangdai Leng,&nbsp;Yantao Luo,&nbsp;Regina Maass,&nbsp;John D. West","doi":"10.1029/2025JB031367","DOIUrl":"https://doi.org/10.1029/2025JB031367","url":null,"abstract":"&lt;p&gt;The bottom of Earth's mantle hosts strong seismic wave speed heterogeneities. These are commonly detected via forward modeling of seismic waveforms, which can include time-consuming waveform synthesis and visual inspection. Furthermore, such imaging has been most commonly carried out with waves that have limited global coverage. In this work, we investigate the efficacy of the diffracted S (&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;S&lt;/mi&gt;\u0000 &lt;mtext&gt;diff&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{S}}_{text{diff}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;) wavefield, which has global coverage to map core-mantle boundary heterogeneity. We implement a Kirchhoff migration algorithm to objectively investigate the presence or absence of postcursors to &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;S&lt;/mi&gt;\u0000 &lt;mtext&gt;diff&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{S}}_{text{diff}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, caused by ultralow velocity zones (ULVZs) and other sharp velocity contrasts. Our approach makes use of the expected moveout of ULVZ-generated &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;S&lt;/mi&gt;\u0000 &lt;mtext&gt;diff&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{S}}_{text{diff}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; postcursors as a function of distance from great-circle path at the base of the mantle. We investigate epicentral distances &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;&gt;&lt;/mo&gt;\u0000 &lt;mn&gt;95&lt;/mn&gt;\u0000 &lt;mo&gt;°&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${ &gt;} 95{}^{circ}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, where &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;S&lt;/mi&gt;\u0000 &lt;mtext&gt;diff&lt;/mtext&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${mathrm{S}}_{text{diff}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; includes asymptotic S/ScS up to diffraction. We test the algorithm using synthetic waveforms calculated for models that include lowermost mantle wavespeed heterogeneity via a recently proposed hybrid simulation approach. Our results demonstrate that the migration approach, when applied to a single event, can well resolve the location of heterogeneity structures in the azimuthal direction, but is less accurate at constraining the along-great circle path location. To loca","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB031367","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144197500","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":"Machine Learning-Based Detection and Localization of Tectonic Tremors in the Japan Trench","authors":"Kodai Sagae,&nbsp;Masayuki Kano,&nbsp;Suguru Yabe,&nbsp;Takahiko Uchide","doi":"10.1029/2025JB031348","DOIUrl":"https://doi.org/10.1029/2025JB031348","url":null,"abstract":"<p>Shallow tectonic tremors near trenches have been detected due to the advancement of offshore observation networks. Traditionally, tremors were identified by cross-correlating envelope waveforms between seismic stations. However, this method has struggled to differentiate tremor signals from earthquakes and sometimes missed tremors during active tremor episodes. Addressing these challenges is crucial for monitoring tremors in seismically active regions, such as the Japan Trench. We developed a machine learning-based tremor monitoring system using a dense network of cable-type ocean-bottom seismometers (S-net) in the Japan Trench. The system analyzed continuous waveforms recorded from August 2016 to August 2024. Our analysis detected seven times more tremors than the previous study using envelope cross-correlation. The newly identified tremors expanded the known spatial distribution of tremor activity, both along the strike and dip, revealing a complementary spatial relationship between tremors and earthquakes. Additionally, our catalog improved temporal resolution, uncovering spatiotemporal patterns of tremors synchronized with slow slip events. Seismic energy rates of tremors were calculated, showing spatial variations along the strike and dip, with higher rates near asperities of large earthquakes. A positive correlation between energy rates and recurrence intervals was found, suggesting that these spatial variations reflect frictional heterogeneities on plate boundaries. The enhanced spatiotemporal resolution of our tremor catalog provides valuable insights into the relationship between slow and fast earthquakes.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB031348","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179418","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":"Effusion Rate Trends at Piton de la Fournaise: A Review of 24 Years of Space-Based Thermal Observation","authors":"Adele Campus,&nbsp;Nicolas Villeneuve,&nbsp;Oryaëlle Chevrel,&nbsp;Aline Peltier,&nbsp;Andrea Di Muro,&nbsp;Diego Coppola","doi":"10.1029/2024JB030962","DOIUrl":"https://doi.org/10.1029/2024JB030962","url":null,"abstract":"<p>We combined thermal satellite imagery from Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) instruments to reconstruct the effusion rate trends in terms of Time Averaged Discharge Rate (TADR) of 37 eruptions (2000–2023) at Piton de la Fournaise (La Réunion, France). The analysis of quantitative data on durations, locations, final erupted volumes, and TADR trends reveal the occurrence of five groups of eruptions. Group 1: eruptions at or near the summit, low volumes, variable durations, and low, almost steady TADR. Group 2: eruptions located over the entire edifice, low volumes, short durations, and a single-pulse of effusion. Group 3: eruptions located in the S-SE sector, moderate volumes, long durations, and exponentially decreasing TADR. Group 4: eruptions in the N-E-S sectors, moderate volumes, long durations, and waning-waxing TADR trends. Group 5: eruptions located in N-E-S sectors, high volumes, and complex trends. Recognizing different groups unravels the complex eruptive patterns of Piton de la Fournaise, only partially compatible with the “pressure-cooker” model usually invoked in closed-vent basaltic contexts. Extending the analysis back to 1998 reveals that although the long-term lava output rate has remained nearly constant (∼0.7 m³/s, steady-state condition), the occurrence and frequency of different eruptive groups changed after April 2007 summit caldera collapse. Our analysis underlines that: (a) the potential occurrence of Groups 4–5 events in ihabithed areas makes them the most hazardous, (b) the 2007 collapse modified magma transfer from the deep storage zone to the surface, but not the steady-state behavior of the volcano.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030962","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171922","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":"Bi-Material Effects on Critical Jump Distance Over Step-Overs","authors":"Feng Hu,&nbsp;David D. Oglesby,&nbsp;Wenqiang Zhang,&nbsp;Zeyu Lu","doi":"10.1029/2024JB030992","DOIUrl":"https://doi.org/10.1029/2024JB030992","url":null,"abstract":"<p>Step-overs can impede rupture propagation, but if breached, they may generate a large destructive earthquake. By performing dynamic rupture simulations on step-overs in both homogeneous and bi-material media, we demonstrate that the bi-material effect significantly influences the critical jump distance, the maximum jump step width that a rupture can jump across. In the positive direction, which is defined as the direction of motion of the softer material, the critical jump distance is greatly enlarged, especially on the compliant side, because of the existence of a tensile normal stress pulse and large slip pulse. In the homogeneous case the rupture can jump only a 1 km releasing step and is stopped by a 1 km restraining step. In contrast, with a 20% material contrast in wave velocity, the critical jump distance increases to 11 km for restraining steps, and 2 km for releasing steps. In the negative direction, supershear rupture is easier to generate because of stress perturbation beyond the rupture front. Besides the Burridge-Andrews supershear, direct-transition supershear can also be noticed in the negative direction under certain condition. However, the critical jump distance in the negative direction is still suppressed because of the dominant bi-material effect over the supershear effect. Our study may shed light on the earthquake hazard assessment due to step-overs in bi-material media.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171993","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":"The Influence of Melt Composition, Temperature, Crystallinity and Water Content on Eruptive Style and Eruption Rate: Insights From a Conduit Model of Magma Ascent","authors":"Angelo Castruccio,&nbsp;Alejandro Rebolledo,&nbsp;Ignacio Gómez","doi":"10.1029/2024JB030599","DOIUrl":"https://doi.org/10.1029/2024JB030599","url":null,"abstract":"<p>We developed a conduit model of magma ascent to the surface, to understand the influence of input parameters like temperature, crystallinity, water content and depth of reservoir on the eruption rate and style of volcanic eruptions. The main novelty of this model over previous ones is that conduit radius, initial overpressure at the conduit inlet and initial bubble number density are not free parameters chosen by the user but are calculated by the code based on the previously mentioned inputs. We also introduce a simplified model of bubble coalescence to include in the analysis the ascent dynamics of low viscosity magmas. Our test results indicate that high crystal content and low- and high-end water contents favor effusive eruptions. Water content has a limited effect on eruption rate of explosive eruptions as the higher content of volatiles is compensated by a lower viscosity that promotes a smaller stable conduit radius. We tested the model with historical eruptions, ranging from low viscosity basaltic andesites to rhyolites, in order to assess the capability of the model to reproduce the eruption style and eruption rate. The model can predict the occurrence of explosive eruptions (Plinian, sub-Plinian, Strombolian and paroxysmal Hawaiian styles) and effusive eruptions and the order of magnitude of their eruption rates, giving new insights into the main controlling factors of volcanic activity.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179368","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":"Non-Hertzian Stress Fields in Simulated Porous Sandstone Grains and Implications for Compactive Brittle Failure—A High-Resolution FEM Approach","authors":"Takahiro Shinohara,&nbsp;Cedric Thieulot,&nbsp;Christopher J. Spiers,&nbsp;Suzanne J. T. Hangx","doi":"10.1029/2024JB030818","DOIUrl":"https://doi.org/10.1029/2024JB030818","url":null,"abstract":"<p>Fluid extraction from sandstone reservoirs leads to reservoir compaction, potentially inducing surface subsidence and seismicity, as observed in the Groningen Gas Field, Netherlands. Such compaction is partly elastic, but can additionally be caused by instantaneous plastic and rate/time-dependent processes, such as subcritical crack growth, meaning that compaction may continue even if production is stopped. Despite the need to evaluate the impact of post-abandonment reservoir behavior (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 </mrow>\u0000 <annotation> ${ &gt;} $</annotation>\u0000 </semantics></math>10–100 years), few mechanism-based, rate/time-dependent compaction laws exist. Compaction due to grain breakage, either via critical or subcritical crack growth, is driven by tensile stresses acting on surface and volume flaws. We performed high-resolution 3D linear elastic finite element method simulations on simplified grain assemblies to investigate the effect of stress–strain boundary conditions, porosity and mineralogical variations on grain-scale stress fields. Our simulations showed tensile stress concentrations at grain contact edges and on pore walls, which increased in magnitude with increasing aggregate porosity and local porosity variation. The fraction of surface area with tensile stresses sufficient to extend flaws with a size up to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>30</mn>\u0000 <mspace></mspace>\u0000 <mi>μm</mi>\u0000 </mrow>\u0000 <annotation> $30hspace*{.5em}mathrm{mu m}$</annotation>\u0000 </semantics></math> showed a clear correlation with compactive yield envelopes for the Groningen reservoir sandstone. This suggests that compactive failure is related to the probability of pre-existing surface flaws, falling in a pore surface region where the Griffith criterion is satisfied. A preliminary, time-independent failure probability model, using the observed tensile stress distribution, qualitatively predicts a non-linear increase in grain cracking during deviatoric loading, and suggests a new route to predict sandstone compaction through brittle grain failure.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030818","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144148589","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}