Journal of Geophysical Research: Solid Earth最新文献

{"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}

{"title":"Geodetic Monitoring of Elastic and Inelastic Deformation in Compacting Reservoirs Due To Subsurface Operations","authors":"Yuexin Li,&nbsp;Mateo Acosta,&nbsp;Krittanon Sirorattanakul,&nbsp;Stephen Bourne,&nbsp;Jean-Philippe Avouac","doi":"10.1029/2024JB030794","DOIUrl":"10.1029/2024JB030794","url":null,"abstract":"<p>A variety of geo-energy operations involve extraction or injections of fluids, including hydrocarbon production or storage, hydrogen storage, CO₂ sequestration, and geothermal energy production. The surface deformation resulting from such operations can be a source of information on reservoir geomechanical properties as we show in this study. We analyze the time-dependent surface deformation in the Groningen region in northeastern Netherlands using a comprehensive geodetic data set, which includes InSAR (Radarsat2, TerraSAR-X, Sentinel-1), GNSS, and optical leveling spanning several decades. We resort to an Independent Component Analysis (ICA) to isolate deformation signals of various origins. The signals related to gas production from the Groningen gas field and from seasonal storage at Norg Underground Gas Storage are clearly revealed. Surface deformation associated to the Groningen reservoir show decadal subsidence, with spatially variable subsidence rates dictated by local compressibility. The ICA reveals distinct seasonal fluctuations at Norg, closely mirroring the variations of gas storage. By comparing the observed long-term subsidence within the Groningen reservoir and seasonal oscillations at Norg from a linear poroelastic compaction model, we quantify the fraction of inelastic deformation of the reservoir in space and time and constrain the reservoir compressibility. In Groningen, increased compressibility indicates inelastic compaction that has built over time and might account for as much as 20% of the total compaction cumulated until 2021, while Norg shows no signs of inelastic deformation and a constant compressibility. This study provides a methodology to monitor and calibrate models of the subsurface deformation induced by geo-energy operations or aquifer management.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660586","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 More the Merrier—Multi-Frequency Magnetic Susceptibility of Loess and Palaeosols as a Sensitive Climate Proxy","authors":"Ramona Schneider,&nbsp;Bjarne Almqvist,&nbsp;Peter Svedlindh,&nbsp;Daniel Hedlund,&nbsp;Jakob Thyr,&nbsp;Redzhep Kurbanov,&nbsp;Thomas Stevens","doi":"10.1029/2024JB029727","DOIUrl":"10.1029/2024JB029727","url":null,"abstract":"<p>Environmental magnetism, including the use of magnetic susceptibility (MS), has formed the backbone of analyzing past terrestrial climate dynamics recorded in loess deposits world-wide. However, the nature of MS signal response and frequency dependence (<i>χ</i>_FD) varies between loess sequences, which can limit the applicability of the approach. Here, we explore how measuring MS using multiple alternating-current field frequencies can transform our understanding of the past climate record in loess. We compare loess MS data measured at 15 different frequencies from diverse environments across the Northern Hemisphere, and provide high-resolution data for a late Quaternary loess-paleosol section in Tajikistan. Additionally, we study the magnetic mineral composition in selected Tajik loess samples using rock magnetic methods and Raman spectroscopy and assess the usefulness of calculating superparamagnetic nanoparticle (SP) size distributions from multi-frequency magnetic susceptibility. Our results demonstrate that using this approach to determine <i>χ</i>_FD has several advantages over widely used dual-frequency approaches: (a) Inclusion of a wider grain size range of magnetism-bearing SP particles in measuring <i>χ</i>_FD, allowing for a more complete analysis of the environmental drivers behind the MS signal; (b) Higher sensitivity of the <i>χ</i>_FD palaeoclimate proxy to climatic changes; and (c) Increased statistical meaningfulness of the <i>χ</i>_FD proxy by allowing quantification of uncertainty. Our approach is particularly beneficial for understanding sites characterized by low-susceptibility samples and potentially diverse processes of magnetic enhancement. However, we advocate its routine use even in more typical loess sequences due to its greater sensitivity to climatic changes and better understanding of inherent proxy uncertainties.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029727","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143661038","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":"Early Viscoelastic Relaxation and Afterslip Inferred From the Postseismic Geodetic Observations Following the 2021 Mw7.4 Maduo Earthquake","authors":"Jingwei Li,&nbsp;Yunguo Chen,&nbsp;Zizhan Zhang,&nbsp;Shengpeng Zhang,&nbsp;Haoming Yan,&nbsp;Meng Chen,&nbsp;Wei Zhan,&nbsp;Yongying Zhang,&nbsp;Wei Xu,&nbsp;Runzhi Sun,&nbsp;Gang Chen,&nbsp;Yanqiang Wu","doi":"10.1029/2024JB030466","DOIUrl":"https://doi.org/10.1029/2024JB030466","url":null,"abstract":"<p>The 2021 Mw7.4 Maduo (China) earthquake is the first major earthquake within the Bayan Har block in recent decades. Despite this, little monitoring data has so far been undertaken to fully understand the postseismic mechanisms. This paper presents the first-year deformation within ∼350 km from the rupture area following the 2021 Maduo earthquake by Global Navigation Satellite System and Interferometric Synthetic Aperture Radar observations. We use a three-dimensional finite element model and kinematic inversion method to investigate the mechanisms of early postseismic displacement of the 2021 Maduo earthquake and constrain the lithospheric rheology in northeastern Tibet. The observations reveal that the first-year postseismic displacements reach ∼40 mm in the near-field and 1∼2 mm in the far-field. The preferred model results show that the afterslip and viscoelastic relaxation jointly play a dominant role in controlling the early postseismic displacement, while the effects of poroelastic rebound are negligible. The afterslip mainly occurs at 0–45 km depth along the main and branch faults, where the maximum slip is ∼0.1 m. The optimal steady-state viscosities of the lower crust and upper mantle are 2–5 × 10¹⁹ Pa s and 3–10 × 10¹⁹ Pa s, respectively. This implies a weak lower crust may exist beneath northeastern Tibet. Besides, our results indicate that shallow afterslip may have a mutually reinforcing relationship with aftershocks. Ignoring early viscoelastic relaxation effect could lead to a significant increase in deep afterslip. Our findings demonstrate that a wider range of observations might provide the potential capability to distinguish between afterslip and viscoelastic relaxation effects.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 3","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143645857","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}