Journal of Geophysical Research: Solid Earth最新文献

{"title":"The Effect of Hydrate Formation Conditions on the Mechanics of Laboratory Methane Hydrate-Bearing Sediments","authors":"L. Rake,&nbsp;S. Pinkert","doi":"10.1029/2024JB029217","DOIUrl":"10.1029/2024JB029217","url":null,"abstract":"<p>The mechanics of methane hydrate-bearing sediments (MHBS) have been broadly investigated over recent years in the context of methane-gas production or climate-change effects. Their mechanical investigation has mainly been carried out using models constructed from experimental data obtained for laboratory-formed MHBS. Along with the dominant effects of hydrate saturation and morphology within the host soil pores, this study recognizes the effective pressure at which the hydrate is formed as a key factor in the MHBS mechanics. A state-of-the-art experimental study has been conducted in order to isolate the effect of the hydrate formation pressure, for use as a model parameter. Two generalized mechanical prediction models that incorporate the effect of the hydrate formation pressure are developed in this work: (a) an analytical shear strength prediction, and (b) an empiric graphical model for predicting volumetric changes along a given stress path. The models are related to a novel data representation which enables the analysis of a few individual test outcomes as a whole, through a volume-change mapping that describes the complex influence of the volumetric effect of hydrate in MHBS, under combined hydrostatic and deviatoric loading scenarios. In this study, we delve into a specific configuration of hydrate morphology, hydrate saturation, and host soil type, enabling a distinctive fundamental geotechnical investigation and the development of a conceptual modeling approach. The paper describes the approaches by which the MHBS properties can be extracted for other MHBS samples (than those examined in this work) having different host soils and hydrate pore-space morphologies.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 10","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029217","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142317608","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":"Tectonic Quiescence in Actively Extending Back-Arc Regions","authors":"A. Beniest,&nbsp;A. Dannowski,&nbsp;M. Schnabel,&nbsp;H. Kopp,&nbsp;the SO267 Scientist Party","doi":"10.1029/2024JB029236","DOIUrl":"https://doi.org/10.1029/2024JB029236","url":null,"abstract":"<p>We analyzed refraction and reflection seismic data covering the Central Lau Spreading Center (CLSC) and the Tonga volcanic arc at 18°S in the Pacific Ocean to investigate tectonic inactivity in actively extending back-arc systems. Our P-wave travel time tomography shows a characteristic 6–8 km thick back-arc crust beneath and around the CLSC and a ∼13 km thick arc-crust at the eastern end of our profile, which corresponds to the Tonga volcanic arc. Lower crustal velocities increase to 7.5 km/s toward the volcanic arc, marking the transition from back-arc to arc crust. These high P-wave velocities can be explained by a high pyroxene content in the lower crust originating from depleted melts. Our seismic reflection data show steep normal faults below the CLSC and volcanic structures closer to the volcanic arc, without a tectonically inactive zone (also knows as the “diffuse plate boundary”) in between. Based on our results, we suggest that the Niuafo'ou and Tonga microplates should be treated as one tectonic plate with local zones of intra-plate deformation that are separated by zones that are tectonically quiet.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029236","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142316707","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":"Modeling Subduction With Extremely Fast Trench Retreat","authors":"Diandian Peng,&nbsp;Dave R. Stegman","doi":"10.1029/2024JB029240","DOIUrl":"https://doi.org/10.1029/2024JB029240","url":null,"abstract":"<p>The Tonga-Kermadec subduction zone exhibits the fastest observed trench retreat and convergence near its northern end. However, a paradox exists: despite the rapid trench retreat, the Tonga slab maintains a relatively steep dip angle above 400 km depth. The slab turns flat around 400 km, then steepening again until encountering a stagnant segment near 670 km. Despite its significance for understanding slab dynamics, no existing numerical model has successfully demonstrated how such a distinct slab morphology can be generated under the fast convergence. Here we run subduction models that successfully reproduce the slab geometries while incorporating the observed subduction rate. We use a hybrid velocity boundary condition, imposing velocities on the arc and subducting plate while allowing the overriding plate to respond freely. This approach is crucial for achieving a good match between the modeled and observed Tonga slab. The results explain how the detailed slab structure is highly sensitive to physical parameters including the seafloor age and the mantle viscosity. Notably, a nonlinear rheology, where dislocation creep reduces upper mantle viscosity under strong mantle flow, is essential. The weakened upper mantle allows for a faster slab sinking rate, which explains the large dip angle. Our findings highlight the utilizing rheological parameters that lead to extreme viscosity variations within numerical models to achieve an accurate representation of complex subduction systems like the Tonga-Kermadec zone. Our study opens new avenues for further study of ocean-ocean subduction systems, advancing our understanding of their role in shaping regional and global tectonics.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029240","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313389","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":"Physics-Based Forecasts of Eruptive Vent Locations at Calderas","authors":"L. Mantiloni,&nbsp;E. Rivalta,&nbsp;K. R. Anderson,&nbsp;T. Davis,&nbsp;L. Passarelli","doi":"10.1029/2023JB028409","DOIUrl":"10.1029/2023JB028409","url":null,"abstract":"<p>Constraining stresses in the Earth's crust in volcanic regions is critical for understanding many mechanical processes related to eruptive activity. Dike pathways, in particular, are shaped by the orientation of principal stress axes. Therefore, accurate models of dike trajectories and future vent locations rely on accurate estimates of stresses in the subsurface. This work presents a framework for probabilistic constraint of the stress state of calderas by combining three-dimensional physics-based dike pathway models with observed past vent locations using a Monte Carlo approach. The retrieved stress state is then used to produce probability maps of future vent opening across a caldera. We test our stress inversion and vent forecast approach on synthetic scenarios, and find it successful depending on the distribution of the available vents and the complexity of the volcano's structural history. We explore the potential and limitations of the approach, show how its performance is sensitive to the assumptions in the models and available prior information, and discuss how it may be applied to real calderas.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JB028409","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273665","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":"Overriding Plate Deformation Controls Inferences of Interseismic Coupling Along the Himalayan Megathrust","authors":"Dibyashakti Panda,&nbsp;Eric O. Lindsey","doi":"10.1029/2024JB029819","DOIUrl":"10.1029/2024JB029819","url":null,"abstract":"<p>The seismic hazard along the Himalayan arc remains a focus of discussion due to its huge potential societal impact. Taking advantage of modern, dense geodetic observations, several attempts have been made to provide a clear picture of the present-day rate of strain accumulation caused by interseismic coupling on the Main Himalayan Thrust (MHT). However, there are differing opinions regarding the interpretation of spatial variation in interseismic coupling along some parts of the arc. Critically, the resolution of heterogeneity of coupling is limited due to sparse geodetic observations in some areas. In the present work, we use an updated compilation of all available Global Navigation Satellite System (GNSS) data along the Himalayan arc and a suite of kinematic block models to account for deformation within the overriding plate to characterize the status of interseismic plate coupling. Our results show that the MHT is highly coupled (&gt;0.8) along its entire length and the coupling distribution is nearly binary along-dip. This translates to a high seismic hazard in the densely populated Indo-Gangetic plains with a seismic moment accumulation of one Mw 8.7 megathrust earthquake per 100 years. Our results suggest that previously inferred low coupling zones along the MHT are possible manifestations of block modeling artifacts, where the fault segments in the overriding plate control the megathrust slip distribution more strongly than structures within the Indian lithosphere. This result highlights a strong need for better characterization of deforming structures in the overriding plate within the Himalayas and southern Tibetan plateau.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029819","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273685","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":"Frictional Properties of Simulated Fault Gouges Subject to Normal Stress Oscillation and Implications for Induced Seismicity","authors":"Bowen Yu,&nbsp;Jianye Chen,&nbsp;Christopher J. Spiers,&nbsp;Shengli Ma,&nbsp;Miao Zhang,&nbsp;Wenbo Qi,&nbsp;Hao Chen","doi":"10.1029/2024JB029521","DOIUrl":"https://doi.org/10.1029/2024JB029521","url":null,"abstract":"<p>Under critical conditions where experimental fault slip exhibits self-sustained oscillation, effects of normal stress oscillation (NSO) on fault strength and stability remain poorly understood, as do potential effects of NSO on natural and induced seismicity. In this study, we employed double direct-shear testing to investigate the frictional behavior of a synthetic, slightly velocity-weakening (SVW) fault gouge (characterized by self-sustained oscillation under quasi-static shear loading), when subjected to NSO at different amplitudes (5%–20% of 5 MPa) and frequencies (0.001–1 Hz). During the experiment, fault displacement and gouge layer thickness were measured. Transmitted ultrasonic waves were also employed to probe grain contact states within the gouge layer. Our results show that fault weakening and unstable slip can be triggered at NSO frequencies ranging from 0.03 to 0.1 Hz and amplitudes exceeding 5%. Interestingly, an amplified shear stress drop and weakening effect were observed when the NSO frequency fell in 0.05–0.1 Hz. Analysis of transmitted ultrasonic waves in tests on the SVW gouge revealed fault dilation, accompanied by unstable slip and weakening. By extending an existing microphysical model (the “Chen-Niemeijer-Spiers [CNS]” model), to account for elastic effects of NSO on gouge microstructure and grain contact state, the mechanical and wave data obtained in our experiments on the SVW gouge was reproduced, suggesting an approach for modeling fault instability under upper crustal (SVW) conditions where normal stress is perturbed by subsurface operations, such as periodic gas storage stimulation of reservoir formations.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142276564","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":"Opposite Variations for Pore Pressure on and off the Fault During Simulated Earthquakes in the Laboratory","authors":"Dong Liu,&nbsp;Nicolas Brantut,&nbsp;Franciscus M. Aben","doi":"10.1029/2024JB028829","DOIUrl":"10.1029/2024JB028829","url":null,"abstract":"<p>We measured the spatiotemporal evolution of pore pressure on- and off-fault during failure and slip in initially intact Westerly granite under triaxial conditions. The pore pressure perturbations in the fault zone and the surrounding bulk presented opposite signs upon shear failure, resulting in large pore pressure gradients over small distances (up to 10 MPa/cm). The on-fault pore pressure dropped due to localized fault dilation associated with fracture coalescence and fault slip, and the off-fault pore pressure increased due to bulk compaction resulting from the closure of dilatant microcracks mostly parallel to the maximum compression axis. We show that a reduction in bulk porosity and relatively undrained conditions during failure are necessary for the presence of the off-fault pore pressure elevation. Considering this phenomenon as a consequence of a main shock, we further show that off-fault pore pressure increase has the potential to trigger neighboring fault instabilities. In nature, we expect the phenomenon of off-fault pore pressure increase to be most relevant for misoriented faults, where the pre-rupture stresses can be large enough to reach the dilatancy threshold in the wall rocks.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB028829","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247171","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":"Structural Evolution of Basaltic Melts in the Deep Earth: Insights From High-Pressure Sound Velocity of Glass","authors":"Charlotte Trubowitz,&nbsp;Motohiko Murakami,&nbsp;Sylvain Petitgirard,&nbsp;Christian Liebske,&nbsp;Catherine McCammon","doi":"10.1029/2024JB028969","DOIUrl":"10.1029/2024JB028969","url":null,"abstract":"<p>The densification mechanisms of silicate melts under high pressure are of key interest in understanding the evolution of the early Earth and its present-day internal structure. Here, we report Brillouin spectroscopy-derived transverse acoustic wave velocities <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <mfenced>\u0000 <msub>\u0000 <mi>V</mi>\u0000 <mi>S</mi>\u0000 </msub>\u0000 </mfenced>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> $left({V}_{S}right)$</annotation>\u0000 </semantics></math> from a basaltic glass at high pressures up to 163 GPa and ambient temperature to provide insight into pressure-induced changes in its elasticity and, by extension, its density. We find that the pressure dependence of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <msub>\u0000 <mi>V</mi>\u0000 <mi>S</mi>\u0000 </msub>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${V}_{S}$</annotation>\u0000 </semantics></math> below 110–140 GPa follows a trend nearly tantamount to those of pyrolite and Fe- and (Fe,Al)-bearing MgSiO₃ glasses, indicating that the large compositional differences among these glasses do not exert variable acoustic wave velocity trends. However, at higher pressures we observe a small departure from the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <msub>\u0000 <mi>V</mi>\u0000 <mi>S</mi>\u0000 </msub>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${V}_{S}$</annotation>\u0000 </semantics></math> profiles of the Al-poor compositions toward higher acoustic wave velocities to eventually become stiffer. This pressure-induced steepening in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <msub>\u0000 <mi>V</mi>\u0000 <mi>S</mi>\u0000 </msub>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${V}_{S}$</annotation>\u0000 </semantics></math> is comparable to that of (Mg, Fe, Al)(Si, Al)O₃ glass, and suggests a possible structural change toward a denser state caused by more rapidly changing Al–O coordination in network-forming Al. Coupled with the high Fe content in basalt, this may render basaltic melt denser than surrounding minerals in the deep lower mantle, and may provide an additional mechanism for the existence of ultralow-velocity zones.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB028969","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247160","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 Heat Flow Measurements Offshore Montserrat: Advective Heat Flow Detected via MeBo Borehole Temperature Logging","authors":"Matthew J. Hornbach,&nbsp;Michel Kühn,&nbsp;Tim Freudenthal,&nbsp;Jordan Graw,&nbsp;Christian Berndt,&nbsp;Katrin Huhn-Frehers,&nbsp;S. F. L. Watt,&nbsp;Benjamin J. Phrampus,&nbsp;Warren T. Wood","doi":"10.1029/2023JB028651","DOIUrl":"10.1029/2023JB028651","url":null,"abstract":"<p>New heat flow measurements collected at the Lesser Antilles Arc using a Hybrid Lister-Outrigger probe and a new logging-while-tripping MeBo70 drilling approach provide the first high-resolution (meter-to-cm-scale) temperature-depth measurements across the Lesser Antilles volcanic arc and offer new insight into heat and fluid transfer at a convergent oceanic margins. At multiple sites where logging-while-tripping MeBo temperature measurements were made, temperature increases linearly with depth in shallowly buried hemipelagic sediment but is isothermal or significantly hotter in deeper, courser-grained sediments associated with mass flows. We interpret these isothermal zones as regions where advective heat flow—perhaps caused by convection or pressure-driven advection—dominates. The implication is that apparently conductive heat flow regimes observed in the shallowest upper 5–10 m of hemipelagic sediment across the Lesser Antilles Arc measured using standard lister-type probes may often unknowingly be influenced by deeper, advective flow along buried mass transport deposits at this site. Since mass transport deposits are ubiquitous on convergent margins, higher permeability mass transport deposits may play a fundamental and previously unrecognized role in fluid and heat transport.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273667","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":"Branched Conduit Structure Beneath the Active Craters of Sakurajima Volcano Inferred From Muography","authors":"László Oláh,&nbsp;Gergő Hamar,&nbsp;Takao Ohminato,&nbsp;Hiroyuki K. M. Tanaka,&nbsp;Dezső Varga","doi":"10.1029/2023JB028514","DOIUrl":"10.1029/2023JB028514","url":null,"abstract":"<p>Observing in-conduit physical mechanism underlying the switching of eruptive activity between the craters of multi-vent volcanoes could contribute to hazard assessment at these complex volcanic edifices. We performed monitoring of mass density changes beneath two active craters of Sakurajima volcano in Kyushu, Japan between September 2018 and July 2023 with cosmic-ray muography. From December 2022, the mass density decreased beneath Minamidake crater and increased beneath Showa crater in accordance with a switch of eruptive activity from Minamidake crater to Showa crater. Plug formation and convective magma degassing processes have been observed with muography in accordance with the deformation of the surface of volcanic edifice measured by Interferometric Synthetic Aperture Radar. We found a moderate inverse correlation with a Pearson’s coefficient of −0.52 between the mass densities observed beneath the two active craters throughout the entire period. The inverse correlation of mass densities indicates a magmatic gas flux dynamics which characterizes a branched conduit structure. Muography thus reveals the shallow magmatic processes during switching of eruptive activity between the craters of multi-vent volcanoes and allows to infer to the conduit structure.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JB028514","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247163","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}