Journal of Seismology最新文献

{"title":"Physics-based 3D ground motion simulations of the 1703 L’Aquila earthquake: from historical reconstruction to seismic scenarios","authors":"F. Di Michele,&nbsp;D. Pera,&nbsp;E. Stagnini,&nbsp;I. Mazzieri,&nbsp;J. B. May,&nbsp;V. Kastelic,&nbsp;M. M. C. Carafa,&nbsp;B. Rubino,&nbsp;R. Aloisio,&nbsp;C. Smerzini,&nbsp;P. Marcati","doi":"10.1007/s10950-026-10434-z","DOIUrl":"10.1007/s10950-026-10434-z","url":null,"abstract":"<div><p>The city of L’Aquila (central Italy) and its surrounding villages have been struck several times throughout history by strong earthquakes, most recently by the <span>(M_w)</span> 6.1 event of April 6, 2009. Previously, on February 2, 1703, L’Aquila was partially destroyed by a <span>(M_w)</span> 6.7 earthquake, which has remained in the city’s collective memory as the <i>Grande Terremoto </i> (“Big Earthquake”). In this paper, we present a physics-based simulation of this event, together with a set of plausible scenarios associated with the same fault structure believed to be responsible for the 1703 earthquake. Assuming the geometry of the fault plane as assigned, we simulate 120 stochastic rupture scenarios corresponding to different magnitudes, epicentral locations, and slip distributions, selected within ranges compatible with the available literature. For each scenario, several estimates of macroseismic intensity are obtained from peak ground velocity and peak ground acceleration values using a set of empirical models specifically calibrated for the Italian territory. The performance of the scenarios is then evaluated through comparison with the macroseismic intensity field provided by historical catalogues. This study demonstrates that a satisfactory reconstruction of ground shaking from major historical earthquakes can be achieved using a stochastic source model constrained by a limited amount of ex-ante information. The proposed PBS-based approach helps integrate historical catalogues, filling data gaps. However, it is affected by limitations related to near-source numerical modeling, uncertainties in the empirical correlations used to derive macroseismic intensity, and assumptions on the source geometry. Nevertheless, the generated scenarios provide valuable insights into the potential impacts of future earthquakes with characteristics similar to the investigated event.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-026-10434-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Empirical ground motion equations for the Eastern Alps, Austria","authors":"María del Puy Papí-Isaba,&nbsp;Maurizio Mattesini,&nbsp;Wolfgang Lenhardt,&nbsp;Elisa Buforn","doi":"10.1007/s10950-026-10438-9","DOIUrl":"10.1007/s10950-026-10438-9","url":null,"abstract":"<div><p>We present a new set of region-specific empirical Ground Motion Equations for the transition zone between the southern Vienna Basin and the Eastern Alps, the area with the highest seismic hazard in Austria. The equations include Intensity Prediction Equations for EMS-98 macroseismic intensity, Ground Motion Prediction Equations for four instrumental ground motion variables, and Ground Motion Intensity Conversion Equations to convert instrumental to macroseismic ground motion parameters. The equations are calibrated from seven low-to-moderate-magnitude earthquakes <span>(left(3.0le {M}_{w}le 4.1right))</span> between 2021 and 2024. These events were recorded by a significantly densified seismic network and resulted in the most extensive macroseismic dataset for the region to date, with about 2,000 intensity data points and high-quality waveforms from both permanent and temporary stations. Our equations capture local attenuation characteristics and near-field effects not resolved by existing national models. These GMEs represent an important step towards improving regional seismic hazard assessment and rapid impact estimation for moderate-magnitude earthquakes in this low-to-moderate seismicity area.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-026-10438-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"The enduring vision of Agustín Udías","authors":"Angela Saraò","doi":"10.1007/s10950-026-10439-8","DOIUrl":"10.1007/s10950-026-10439-8","url":null,"abstract":"","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of newly-detected small seismic events in and near the Northern Korean Peninsula from 2004 to 2010: Part I, correlation, detection, and relative locations","authors":"David P. Schaff,&nbsp;Kin-Yip Chun,&nbsp;Won-Young Kim,&nbsp;Paul G. Richards","doi":"10.1007/s10950-026-10435-y","DOIUrl":"10.1007/s10950-026-10435-y","url":null,"abstract":"<div><p>We have detected and located 1,015 seismic events observed at 4 or more stations of the 17-station Dongbei Broadband Seismographic Network (DBN), which operated from June 2004 to September 2010 in Northeast China near the border with the Democratic People’s Republic of Korea (DPRK). We chose 447 master seismic events reported in catalogs published by the International Seismological Centre (ISC), the Korean Meteorological Agency (KMA), the Earthquake Administration of the Jilin Province of China. Using <i>Lg</i> wave-trains of the master events we searched the continuous archive recorded by DBN to detect (via cross-correlation) events similar to the master events. The relative locations of this event-catalog have 95% confidence errors of only 140 m on average. The improvement in locations (compared to the starting locations) can be measured by a factor of 95 reduction in the average standard deviation of the residuals, and by a one to two orders of magnitude reduction in scatter of the double-difference locations as measured by average inter-event separation distance. The natural seismicity rate is lower for this broad area of interest in and near North Korea than for California and China and other seismically-active regions. But it is much higher than was expected for what was previously thought of as a generally aseismic region. This is important to know and recognize for nuclear monitoring – and is important too for an understanding of the distribution of stresses in regions where significant seismic events turn out to have unsuspected low-magnitude aftershocks.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148782131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity of ground motion simulations to regional velocity model uncertainties in Indian subcontinent: Insights from the Mw 7.7 2025 Myanmar earthquake","authors":"M. Naga Tejasri,&nbsp;S. T. G. Raghukanth,&nbsp;Himanshu Mittal","doi":"10.1007/s10950-026-10428-x","DOIUrl":"10.1007/s10950-026-10428-x","url":null,"abstract":"<div><p>The 2025 Myanmar earthquake M_w 7.7, one of the most devastating earthquakes and widely recorded the ground motion shaking in Indian subcontinent. The event caused severe local devastation and also provided valuable insights about the ground motion datasets. In this study, the recorded ground motions are analyzed and physics-based ground-motion simulations are carried out to investigate the sensitivity of the simulations to velocity uncertainties. Strong motion data from Indian seismic networks, together with five near-epicentral IRIS stations, are analyzed using evolutionary power spectral density (EPSD) and response spectra parameters to investigate source, path, and site effects. The analysis revealed a broad attenuation pattern across the Indian subcontinent, with pronounced amplification observed in regions underlain by alluvial deposits, such as the Indo-Gangetic basin, underscoring the role of site effects in modifying ground motion propagation. To complement these observations, physics-based simulations are conducted at the same set of stations using the spectral element method, incorporating seven different velocity models: a default global model, six randomized velocity models with uncertainties in shear wave velocity V_s. A strong agreement between simulated and recorded time histories in the near-field validated both the reported finite-fault rupture model and the adopted simulation framework. In contrast, systematic mismatches in the far-field synthetics highlight the sensitivity of the simulations to regional velocity model uncertainty. Qualitative and quantitative evaluation is performed based on waveform comparisons, peak ground velocity (PGV) residuals, Anderson Goodness-of-Fit (GOF) scores and comparison with existing ground motion models. The results from the randomized models are observed that the better agreement when compared to recordings at several stations. These findings emphasize the importance of detailed soil microzonation, heterogeneity of region velocity structure and improved velocity profiles for India, crucial for advancing regional ground motion prediction and seismic hazard assessment.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress accumulation and seismic hazard in the outer Banda Arc: insights from Coulomb failure stress (ΔCFS) and b-value analysis on Seram Island","authors":"Andri Kurniawan,&nbsp;Andri Dian Nugraha,&nbsp;David Prambudi Sahara,&nbsp;Nicolas Silaen,&nbsp;Dian Kusumawati,&nbsp;Khalil Ibrahim,&nbsp;Pepen Supendi,&nbsp; Karyanto,&nbsp;Muh Sarkowi","doi":"10.1007/s10950-026-10432-1","DOIUrl":"10.1007/s10950-026-10432-1","url":null,"abstract":"<div><p>Understanding the interaction between stress redistribution and seismicity is crucial for assessing seismic hazards in tectonically complex regions like the northern Banda Arc. The Ambon–Seram region of eastern Indonesia features a complex regime of strike-slip, normal, and reverse faulting driven by the high-curvature Banda plate boundary. This study investigates the spatiotemporal evolution of Coulomb Failure Stress changes and b-values across three distinct tectonic domains: Ambon–West Seram, the Kawa Shear Zone, and East Seram. We quantified ΔCFS on specific receiver fault segments at depths of 5, 10, and 15 km across four temporal intervals from 1980 to 2025. Seismicity characteristics were evaluated using an adaptive Voronoi-based approach, incorporating median b-values, Median Absolute Deviation, and the number of valid models to ensure statistical stability. The results reveal pronounced spatial and temporal heterogeneity in stress evolution throughout the study area. The Ambon–West Seram domain exhibits the most persistent stress concentration, particularly along the AMB1, AMB2, and AMB19 fault systems. Notably, the AMB19 segment, associated with the 2019 Mw 6.5 Ambon earthquake, experienced positive Coulomb loading prior to the event, with local ΔCFS values reaching approximately + 0.1 bar during the 2001–2018 period. Following the 2019 earthquake, AMB19 displayed a depth-dependent mechanical response, transitioning into a stress shadow at shallow depths (5 km) while maintaining positive loading at 10 and 15 km. This domain also retains a persistent low b-value anomaly, with median values ranging from 0.65–0.66 before 2019 to 0.62–0.63 thereafter. In contrast, the Kawa Shear Zone exhibits segmented unloading–reloading behavior, with stress loading recurring on the MSL, KWA, ALU, and TLT segments following significant seismic events. East Seram displays highly localized interactions characterized by segment-specific combinations of loading and shadowing on individual faults rather than a uniform regional pattern. Overall, the integration of ΔCFS and adaptive b-values demonstrates that seismic hazard in the northern Banda Arc is strongly controlled by fault segmentation, source mechanisms, and depth-dependent stress transfer. These findings provide a high-resolution, segment-based framework for evaluating stress heterogeneity and future seismic potential in the region.\u0000</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Updated moment magnitude catalog for algeria and adjacent regions (PECAAR v2.0): a foundational dataset for modern seismic hazard analysis","authors":"Fouzi Bellalem","doi":"10.1007/s10950-026-10426-z","DOIUrl":"10.1007/s10950-026-10426-z","url":null,"abstract":"<div><p>A homogeneous, completeness-controlled, and declustered moment-magnitude earthquake catalog is fundamental for reliable seismicity modelling and Probabilistic Seismic Hazard Assessment (PSHA). This study introduces PECAAR v2.0, a substantially updated M_W-referenced catalog for Algeria and adjacent regions, covering the period 1658–2022. This update incorporates previously unused historical and instrumental datasets, adds 1554 new events, and expands the multi-agency database to improve both temporal and spatial coverage. A large multi-agency waveform-based M_W reference dataset from the Western Mediterranean region supports the derivation of ten new regional magnitude-conversion relations for m_b, M_S, M_L, m_bLg, and related scales after inter-agency bias correction and robust outlier filtering. The new relations reduce residual scatter, enhance magnitude stability, and reveal significant scale-dependent biases in commonly used global conversion equations when applied to Northern Algeria. The study presents the first dedicated empirical conversion for European-Mediterranean Seismological Centre (EMSC) m_b magnitudes in the Euro-Mediterranean region and introduces a new calibrated relation for local magnitude (M_L) values from the “Centre National pour la Recherche Scientifique et Technique (CNRST) facilitating more consistent cross-border integration of regional seismic data. Catalogue completeness is extended to 2022 using the framework established in previous studies, resulting in six completeness-consistent intervals and demonstrating that the instrumental period is complete to M_W 3.0 since 2000. Declustering is conducted using a nearest-neighbour space–time–magnitude metric, resulting a physically consistent mainshock catalog. PECAAR v2.0 includes 12,719 homogenized earthquakes and 8449 mainshocks from 11,013 events with M_W ≥ 3.0. This dataset strengthens recurrence modelling, background seismicity estimation, and hazard calculations, providing a modern and reproducible foundation for PSHA and seismotectonic studies in Northern Algeria.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of newly-detected small seismic events in and near the Northern Korean Peninsula from 2004 to 2010: Part II, absolute locations, origin times, and event identification","authors":"David P. Schaff,&nbsp;Kin-Yip Chun,&nbsp;Won-Young Kim,&nbsp;Paul G. Richards","doi":"10.1007/s10950-026-10436-x","DOIUrl":"10.1007/s10950-026-10436-x","url":null,"abstract":"<div><p>We detected, located, analyzed and identified new seismic events from continuous waveforms of the 17-station Dongbei network (DBN) from June 2004 to September 2010 in Northeast China near the border with North Korea. We used 447 master events from the International Seismological Centre (ISC), the Korean Meteorological Agency (KMA), and Jilin Province of China catalogs to detect more events using <i>Lg</i> waves. 1,015 located events were comprised of 140 similar event clusters. About 40% of the events are from 9 earthquake clusters in NE China; 20% of the events were associated with 10 clusters of earthquakes and mining explosions around Pyongyang, North Korea; and nearly 10% of the events are clustered around the east coast of South Korea. The last clusters are remarkable in that master events with magnitude less than 2.0 were used to detect and locate repeating events at a distance 400–500 km away from the 500 km long linear array of stations trending ~ 60º (DBN). Clusters with 95% of their origin times occurring primarily during working hours and working days are likely mining explosions. The binomial test shows as much as 22% to 39% of the detected catalogs verified at 2, 3, and 4 or more stations and six of the nine largest located clusters can be identified as statistically significant explosion clusters. Correlation detectors find large numbers of similar events that can be identified as aftershocks (following Omori’s law), and mining explosions. These methods provide complementary, independent evidence for event identification down to remarkably low magnitude.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards a unified moment magnitude catalog: region-specific magnitude relationships for small to moderate earthquakes (1.4 ≤ ML ≤ 5.0) in Northeastern and Eastern Iran","authors":"Saeid Naserieh,&nbsp;Hadi Ghofrani,&nbsp;Noorbakhsh Mirzaei,&nbsp;Mohsen Dezvareh,&nbsp;Fatemeh Abdi","doi":"10.1007/s10950-026-10427-y","DOIUrl":"10.1007/s10950-026-10427-y","url":null,"abstract":"<div><p>A homogeneous moment magnitude (M_W) catalog is essential for robust seismological analysis and seismic hazard assessment, as M_W provides a physically based measure of earthquake size, in contrast to amplitude-based magnitude scales. In Iran, operational earthquake catalogs predominantly report Nuttli (M_N) and local (M_L) magnitudes, whereas the principal large-scale M_W source, the GCMT catalog, has a magnitude of completeness of 5.3 since 1976. This results in a substantial gap in M_W coverage for small-to-moderate earthquakes. Addressing this gap requires region-specific empirical magnitude-conversion relationships; however, most existing models are reliable only for magnitudes larger than about 3.5. In this study, we develop and validate new regional scaling relationships to convert M_N and M_L to M_W for earthquakes with 1.4 ≤ M_L ≤ 5.0 in northeastern and eastern Iran. For the M_L–M_W conversion, we propose both a piecewise linear model with a breakpoint at M_L = 2.9 and a quadratic model. For M_L ≥ 2.9, the two formulations yield closely consistent estimates, differing by no more than ~ 0.1 magnitude units. At lower magnitudes, systematic divergence emerges; for example, an earthquake with M_L = 1.4 corresponds to M_W ≈ 1.9, indicating a difference of approximately 0.5 units. Our proposed linear M_N–M_W relation, valid over the M_N range of 2.0–4.8, exhibits close agreement with the line M_N = M_W. These empirically robust relationships enable the construction of a consistent M_W catalog by correcting magnitude-dependent biases, thereby providing a reliable foundation for improved seismotectonic interpretation and seismic hazard assessment within the study region. Outside this region, these relationships should be applied only provisionally and with caution until local calibrations are developed.\u0000</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring hydrologically influenced seismic processes in Palghar region using Horizontal-to-Vertical Spectral Ratio (HVSR) analysis","authors":"Srikanth Murarishetti,&nbsp;V. Pavan Kumar,&nbsp;K. Sivaram,&nbsp;M. Shekar,&nbsp;Prakash Kumar","doi":"10.1007/s10950-026-10431-2","DOIUrl":"10.1007/s10950-026-10431-2","url":null,"abstract":"<div><p>Within the fractured Deccan Volcanic Province of western India, the Palghar earthquake swarm region has experienced repeated seismic activity since 2018 and provides an opportunity to investigate seasonal variations in site-response characteristics and shallow subsurface properties. In this study, we applied the diffused-regime earthquake-derived Horizontal-to-Vertical Spectral Ratio (EHVSR), Site-to-Reference Spectral Ratio (SSR), and EHVSR inversion techniques to earthquake recordings from six broadband seismic stations to evaluate seasonal changes in site response and shallow shear-wave velocity (Vs) structure within the upper ~ 250 m. The analyses were performed separately for pre-monsoon (February-June) and monsoon/post-monsoon (July-December) periods. For robustness, bootstrap analysis was performed to evaluate the stability and uncertainty of the EHVSR estimates, with 95% confidence intervals (CI95), while a source-effect analysis was carried out to assess the influence of source characteristics and wavefield composition. The EHVSR results reveal well-defined resonance frequencies (f₀) at each station, but with generally small seasonal variations across most stations, while the spatial variations ranging from approximately 6 to 15 Hz (across the region). In contrast, amplification factors (A₀), site vulnerability indices (<span>({text{K}}_{text{g}})</span>), inversion-derived Vs models, and V_P/V_S ratios exhibit pronounced temporal variability. SSR analyses produce resonance frequencies broadly comparable to those obtained from EHVSR, but with stronger and sharper amplification peaks. SSR-derived amplification factors range from approximately 2.6 to 6.3 and generally exceed the corresponding EHVSR amplitudes. The fair agreement between EHVSR and SSR-derived resonance frequencies supports the robustness of the identified site-response characteristics (mainly f₀). The inversion results indicate subtle reductions in shallow Vs and increases in V_P/V_S ratios at several stations during the monsoon/post-monsoon period, with some of the most pronounced variations observed at KAWA, located closest to the swarm nucleation zone. This study supports the hypothesis of possible hydrological influences associated with monsoonal recharge and fluid circulation within fractured basaltic formations, as similarly suggested by regional studies. The results provide new constraints on the seasonal sub-surface characterization in the Palghar swarm region and demonstrate the usefulness of integrated EHVSR, SSR, and inversion approaches for, seismic microzonation, and long-term monitoring of fluid-driven earthquake sequences in western India.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}