Journal of Seismology最新文献

{"title":"Proposing an optimal input feature combination for estimating ground response spectra using machine learning: a study in New Zealand","authors":"Le-Anh-Nhat Nguyen,&nbsp;Van-Quang Nguyen,&nbsp;Van-Tien Phan,&nbsp;Trong-Kien Nguyen","doi":"10.1007/s10950-026-10387-3","DOIUrl":"10.1007/s10950-026-10387-3","url":null,"abstract":"<div><p>Three machine learning (ML) models, which are Random Forest (RF), Extreme Gradient Boosting (XGB), and hybrid XGB-RF, were employed in this study using the New Zealand ground motion database, with 5% damped pseudo-spectral acceleration (PSA) as the target variable. The relative importance of 15 input features was assessed using four different approaches. Based on the resulting rankings, a sensitivity analysis was conducted to examine the direct impact of each input feature on the prediction accuracy of the models. An optimal combination (CB) consisting of the six most influential features was selected to develop the proposed PSA prediction models. All ML-based models demonstrated strong predictive performance, achieving the coefficient of determination (<span>({R}^{2})</span>) values exceeding 85%, with the hybrid model consistently providing the highest <span>({R}^{2})</span> across all period ranges. Mixed-effects regression was applied to evaluate model uncertainty, including an assessment of the single-site standard deviation. The proposed models were validated by comparing their predictions with those from established ground motion prediction equations (GMPEs) and observed recordings, showing a good agreement in PSA values. Furthermore, the application of these models to Japanese data, due to their similar tectonic environment, indicated their potential to serve as robust foreign prediction models in future regional ground motion studies.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561531","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":"Multiple discrete sources of the Catastrophic 2023 Mw > 6.0 NNW-Herat, Afghanistan, Earthquake Sequence constrained by Teleseismic Data: Resolving blind duplex thrusting rupture propagation and its seismogenesis","authors":"Mustafa Toker,&nbsp;Hatice Durmuş,&nbsp;Murat Utkucu","doi":"10.1007/s10950-026-10377-5","DOIUrl":"10.1007/s10950-026-10377-5","url":null,"abstract":"<div><p>The long-lasting aseismic period of 1200 years in a slowly deforming mountain belt of NW-Afghanistan, isolated from inter-plate settings was disrupted by the 2023 NNW-Herat earthquake sequence. This unusual sequence underscored the critical need for a thorough scientific research in the area, given its rarity. Sparse observational opportunity and absence of an available station network posed a significant challenge in accurately constraining the sequence, resolving the rupture structure, drawing novel hypotheses and raising an open question related to what drives the current sequence in detail. In this study, teleseismic data was used to derive the co-seismic slip distribution associated with this sequence, demonstrating bilateral co-seismic rupture and radial slip propagation patterns with a maximum slip of 75–125 cm. The resolved rupture models constrained from co-seismic deformation suggest that the major slips in the seismic sequence were dominated by the W-E, NW–SE-striking pure thrust faulting concentrated at a shallow focal depth of 8–14 km. This was characterized by N-dipping, low angled sub-horizontal planes of 30°-36° and corresponded to a sliding structure of 85°-124° in a shallow layer, both of which were linked by a \"package\" of bounded, imbricated thrust sheets, collectively known as a “duplex”. These unknown blind ruptures manifested as “isolated compact asperities” with “patched fault slips”, generally corresponding to the four major duplex thrusting events. Given the co-seismic distributional pattern of these slips using the point-source and finite fault-source inversions, these resolved rupture model solutions should be consecutive occurrences of the four events due to a strong blind duplex thrusting interaction. We suggest that the locked duplex package acts as an obstacle to slow-motion collision, and ruptured sequentially in a 32 km-wide and 40 km-long NW-segment of the ~ 700 km-long Herat left-lateral strike-slip fault system to accommodate plate-scale N-S shortening in an area of ~ 1250 km².</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-026-10377-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561502","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":"Ground motion prediction equations for upper-crustal seismicity and soft sediments","authors":"Elmer Ruigrok,&nbsp;Pauline P. Kruiver,&nbsp;Karin van Thienen-Visser,&nbsp;Annemarie G. Muntendam-Bos,&nbsp;Jorien L. N. van der Wal,&nbsp;Caron E. J. Vossen","doi":"10.1007/s10950-026-10384-6","DOIUrl":"10.1007/s10950-026-10384-6","url":null,"abstract":"<div><p>The first detected induced earthquake in the Netherlands was in 1986. Since then, the seismic network has largely been expanded and geared towards recording induced seismicity. Nearly 2000 events have been located and assigned a local magnitude. The impact of these events on the Earth’s surface can be assessed with help of ground motion prediction equations (GMPEs). In this study, we derive these GMPEs. Previously, GMPEs were derived especially for the Groningen gas field, using data recorded at the surface and until approximately 35 km distance. In this study, we include induced seismicity from three other provinces in the north of the Netherlands, and we use recordings until 110 km distance. We compile a database with approximately 45,000 ground motions, most of which are ’free field’ and all of which are on unconsolidated sediments. This database does not only contain ground motions recorded at ground level, but also motions recorded at 200 m depth. These deep recordings have been made in boreholes situated in quite uniform deposits and hence are less perturbed by varying site conditions. This allows derivation of GMPEs that describe well the distance-dependent attenuation resulting from the deep wave propagation. A correction term is implemented when the focal depth is below a thick salt layer, resulting in lower amplitudes near the epicenter. The GMPEs at the Earth’s surface are derived as scaled versions of the deep GMPEs, with the option to add various site terms. The GMPEs have an empirical base for low-magnitude seismicity (1.0<span>(le )</span><i>M</i><span>(le )</span>3.6), epicentral distances between 0 and 110 km and nucleation depths between 2.3 and 4.0 km. Body waves are responsible for the peak ground motions that have been recorded. These body waves yield a complicated attenuation pattern that is incorporated into the GMPEs. Furthermore, the amplification in the top 200 m soil column is found to have a distance dependence, which is included in the surface-level GMPEs. Other tested site terms yield a modest to negligible improvement in explaining the measured ground motions. The models are validated using records from the 2025 Zeerijp M3.4 event, and compared with other recent GMPEs for a similar seismotectonic setting.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-026-10384-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561662","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 2021 Soubella earthquake (Mw4.7), Northeast Algeria: seismotectonic insights, source parameters from empirical green’s function and seismic response spectra analysis","authors":"Oualid Boulahia,&nbsp;El-Mahdi Tikhamarine,&nbsp;Issam Abacha,&nbsp;Sofiane Taki-Eddine Rahmani,&nbsp;Hichem Bendjama,&nbsp;Fethi Semmane,&nbsp;Khaled Roubeche,&nbsp;Hamoud Beldjoudi","doi":"10.1007/s10950-026-10386-4","DOIUrl":"10.1007/s10950-026-10386-4","url":null,"abstract":"<div><p>On February 24, 2021, an earthquake of M_w 4.7 struck near the Soubella Dam in the Hodna Mountain Chain of northeastern Algeria. Focal mechanism solutions indicated two possible fault planes: an E–W-striking reverse fault dipping north and an E–W-striking thrust fault dipping south, both parallel to the major Chott El Hammam Fault (CH-HF). This study investigates the seismotectonic setting, source dynamics, and seismic response of the dam using waveform data from the Algerian Digital Seismic Network (ADSN) and recordings from four strong-motion accelerometers operated by the Agence Nationale des Barrages et Transferts (ANBT) and installed within the dam. Time-domain moment tensor inversion based on full waveform modeling indicates a reverse-faulting mechanism with a seismic moment of M₀ = 1.49 × 10¹⁶ Nm (M_w 4.7) and a centroid depth of 6.2 km. The causative structure is interpreted as either (1) a ramp-flat-ramp fault system associated with the Chott El Hammam Fault (CH-HF) or (2) a segment of the major tectonic contact between the Tellian allochthonous units of Djebel Boutaleb and the autochthonous Miocene formations of the Hodna Basin. Both interpretations are consistent with the regional compressional tectonic regime and provide new constraints on active faulting in southern Tellian Atlas. Dynamic source parameters were estimated using the Empirical Green’s Function (EGF) method, yielding a corner frequency ratio fc(P)/fc(S) of 1.03, indicative of in-phase far-field P- and S-wave radiation. The mean source duration is approximately 0.22 s, consistent with the derived corner frequencies. The rupture is characterized by a small fault radius and a relatively high stress drop, reflecting localized faulting. The frequency-independent quality factor (Q) values were relatively low (Q_P = 22–132, Q_S = 22–184), indicating strong seismic attenuation in the study area. Strong-motion recordings, a peak ground acceleration (PGA) of 0.27 g near the Soubella Dam, approaching design-level values despite the moderate magnitude of the event. This observation raises concerns regarding the adequacy of existing seismic design assumptions. Given the proximity of the dam to an active fault system, the results underscore the need for enhanced structural reinforcement to improve resilience against future near-fault earthquakes.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147561503","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":"Time-domain moment tensor inversion of moderate earthquakes in the northern red sea: Velocity model sensitivity and bootstrap uncertainty quantification","authors":"Mohamed A. Taha,&nbsp;Sayed S. R. Moustafa,&nbsp;Mohamed Metwaly,&nbsp;Ahmad M. Faried","doi":"10.1007/s10950-026-10372-w","DOIUrl":"10.1007/s10950-026-10372-w","url":null,"abstract":"<div><p>This study investigates the source mechanisms and moment tensor parameters of three local earthquakes in the Sharm El-Sheikh–Ras Nasrani region, northern Red Sea, through full-waveform Time Domain Moment Tensor (TDMT) inversion. Seismic waveform data recorded by the Egyptian National Seismic Network (ENSN) were analyzed using a suite of velocity models and source depth configurations to evaluate the robustness and reliability of the inversion procedure. Synthetic Green’s functions were computed for six distinct 1D Earth models to systematically quantify uncertainties arising from subsurface velocity heterogeneity. Optimal moment tensor solutions were identified based on maximum variance reduction and consistency across velocity models. The preferred solutions achieved variance reductions of up to 81.4%, with moment magnitudes ranging from Mw=4.3 to 5.2. The 2024 event exhibited a predominantly double-couple (DC) mechanism (up to 82%), whereas earlier events displayed notable isotropic (ISO) and compensated linear vector dipole (CLVD) components, indicating either complex rupture processes or heightened sensitivity to velocity model assumptions. Uncertainty quantification, performed using the bias-corrected and accelerated (BCa) bootstrap method, provided statistically robust confidence intervals for key source parameters. These results highlight the importance of velocity model selection and depth resolution in TDMT applications and offer a validated framework for seismic source characterization in tectonically complex and data-constrained environments. By integrating full-waveform inversion with rigorous statistical validation, this study provides a robust framework for addressing epistemic uncertainties in earthquake source analysis, enhancing the reliability of seismic hazard assessments in the northern Red Sea region.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560507","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":"Determination of depth-dependent body wave attenuation beneath the Dead Sea Fault system","authors":"Nadav Wetzler,&nbsp;Esteban J. Chaves","doi":"10.1007/s10950-026-10385-5","DOIUrl":"10.1007/s10950-026-10385-5","url":null,"abstract":"<div><p>We derive a regional 1-D body-wave attenuation (Q⁻¹) model for a segment of the Dead Sea Fault System using moderate earthquakes (3.0 ≤ M_W ≤ 4.5). Q_P and Q_S are estimated through spectral modeling of stations within 350 km, with corner frequencies independently constrained using the empirical Green’s function method to reduce trade-offs between source and attenuation parameters. Path-averaged <i>Q</i> values increase approximately linearly with epicentral distance up to ~ 150 km for both P and S waves, followed by a gradual flattening toward an asymptotic regime. This transition is consistent with increasing mantle path contributions associated with the P_g–P_n and S_g–S_n phase crossover rather than an abrupt change in intrinsic attenuation properties. Inversion of the distance-dependent trends yields a layered 1-D <i>Q(z)</i> structure that reflects relatively low attenuation in the upper crust and higher effective <i>Q </i>at greater depths. Residual analysis indicates only modest lateral variability, suggesting that large-scale path effects dominate over local site controls within the resolution of this dataset. The resulting attenuation model provides physically consistent parameters for ground-motion simulations and offers a framework for future three-dimensional attenuation studies along the Dead Sea Fault System.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-026-10385-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147560526","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":"Assessing data requirements for stress drop and high frequency attenuation studies: insights from the North Sea Horda Platform","authors":"Brian Carlton,&nbsp;Bettina P. Goertz-Allmann,&nbsp;Nadege Langet,&nbsp;Olga-Joan Ktenidou","doi":"10.1007/s10950-026-10383-7","DOIUrl":"10.1007/s10950-026-10383-7","url":null,"abstract":"<div><p>We assess the methodological limits of estimating earthquake source (stress drop) and high-frequency energy attenuation (κ) characteristics by analysing a dataset of seismic waveforms recorded between 2000 and 2022 from the Horda platform region of the North Sea. We observe a bias in the source spectra with strong, but artificial, magnitude dependence of stress drop. Synthetic tests demonstrate that this bias could be largely eliminated with increased station coverage and recording bandwidth. The κ results do not exhibit the expected increase with distance, which is believed to be due to pronounced lateral and vertical variations in the anelastic attenuation parameter Q across the region. These variations likely reflect contrasts in sediment thickness and the transition from the offshore sedimentary basin with extensional tectonics to the onshore Scandinavian Shield composed of crystalline bedrock. Preliminary κ values within the first 50–100 km range from 0.009–0.023 s, consistent with weathered to hard-rock site conditions and in alignment with other estimates from stable continental regions. Our analysis reveals the challenges that sparse and uneven station distribution, limited recording bandwidth, and strong geological heterogeneity pose for robust parameter estimation. Improved network coverage—particularly through the deployment of ocean-bottom sensors in offshore areas—and higher sampling rates would substantially enhance the reliability and spatial consistency of κ and stress-drop estimates. Overall, our findings underscore the importance of station coverage, bandwidth, and regional geology, and have implications for seismic hazard assessment in offshore and data-limited environments.\u0000</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-026-10383-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559870","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":"Pitfalls in the management of induced seismicity","authors":"Julian J. Bommer","doi":"10.1007/s10950-026-10366-8","DOIUrl":"10.1007/s10950-026-10366-8","url":null,"abstract":"<div><p>Induced seismicity poses a potential threat to the viability of many energy-related projects involving injection or extraction of fluids. Important advances have been made in terms of protocols to manage induced seismicity in such projects, including guidelines for seismic monitoring and communications prior to operations and following the occurrence of seismic events. However, for such protocols to guarantee successful management of induced seismicity it may be necessary to include additional elements, that have not been explicitly addressed, in the mitigation strategy. These elements, identified from case histories in which induced earthquakes have led to interruption or suspension of operations, can be broadly grouped into two categories: quantification of the seismic risk due to induced earthquakes and effective and balanced risk-based regulation. While clear and effective communication of the risk to the public is often highlighted as a key factor, this requires that the risk is first correctly quantified, and secondly that the regulatory body takes at least partial responsibility for explaining the risk and providing assurance that it is acceptably low. Such action by the regulatory authority would be premised on the basis of the operator demonstrating compliance with risk-based targets, as is done in the nuclear industry. Potential pitfalls in the quantification of the physical risk from induced earthquakes include exaggeration of the impact of small-magnitude events, overly conservative values of the upper bound magnitudes, modelling choices that lead to biased estimates of the hazard due to induced seismicity relative to that from natural earthquakes, and the use of inappropriate risk metrics.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-026-10366-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559999","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":"Regional coulomb stress changes and stress triggering mechanisms of the noto MW7.5 earthquake","authors":"Mingyue Zhou,&nbsp;Zhitong Jin,&nbsp;Yongge Wan,&nbsp;Zhaoxuan Guan","doi":"10.1007/s10950-026-10378-4","DOIUrl":"10.1007/s10950-026-10378-4","url":null,"abstract":"<div><p>Coulomb stress change (ΔCFS) is widely used to evaluate static earthquake triggering, yet threshold-based triggering statistics can be sensitive to assumptions about fault friction, including possible fluid-related weakening, and to hypocentral uncertainty. Using the 2024 Noto <i>M</i>_W7.5 earthquake sequence, we compute static ΔCFS for (i) the <i>M</i>_W5.5 foreshock acting on the <i>M</i>_W7.5 mainshock receiver plane and (ii) the mainshock acting on early aftershocks within the first 51.5 h. To represent plausible time-varying fault strength potentially influenced by fluids, we convert a friction scenario <i>μ</i>(<i>t</i>) into effective friction <i>μ′</i>(<i>t</i>) under isotropic poroelastic relations for two upper-crustal end members, and evaluate ΔCFS at each aftershock’s reported hypocentral longitude, latitude, and depth. The foreshock yields positive ΔCFS on nodal plane II of the mainshock (~ 0.02 – 0.03 MPa for <i>μ′</i> = 0.17 – 0.25), exceeding the commonly used 0.01 MPa benchmark. For 2,982 aftershocks, the fractions with ΔCFS ≥ 0.01 MPa are ~ 39 – 46% across four-time windows (ΔCFS ≥ 0.05 MPa: ~ 36 – 44%), while perturbing hypocenters within location uncertainties produces broad 90% intervals (~ 30 – 58%). Sensitivity tests show that the threshold-based triggering fraction increases monotonically with <i>μ′</i> over 0.20 – 0.80, underscoring the dependence of ΔCFS statistics on frictional assumptions. Deformation and stress calculations indicate hanging-wall uplift and footwall subsidence consistent with reverse faulting, and a heterogeneous horizontal stress field at ~ 10 km depth characterized by NW–SE extension and NE–SW compression. Overall, these results provide a quantitative reference for interpreting ΔCFS-based triggering in the Noto sequence while highlighting key sensitivities in fixed-threshold metrics.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147559552","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":"Tomographic image of shear wave structure of NE India based on analysis of love wave data","authors":"Nongmaithem Menaka Chanu,&nbsp;Naresh Kumar,&nbsp;Sagarika Mukhopadhyay,&nbsp;Sanjay K. Verma,&nbsp;Shantanu Pandey","doi":"10.1007/s10950-026-10379-3","DOIUrl":"10.1007/s10950-026-10379-3","url":null,"abstract":"<div><p>Crust and uppermost mantle shear-wave velocity in northeast India is elaborated based on the non-linear inversion of the Love wave group velocity data. This is the first time Love wave and SH wave tomography have been carried out in this region. We investigated the vertical and lateral variation of the SH wave velocity and the crustal thickness. We used the data from 26 broadband seismic stations that recorded the earthquakes from 2001 to 2015. Group velocity dispersion curves of 228 moderate and higher magnitude earthquakes are inverted to obtain tomography images of group velocities at periods 6–60 s. Low velocity is confined to the Bengal Basin (BB) and the Indo-Burma Ranges (IBR) at short periods. In contrast, high velocity is present in the Shillong Plateau (SP), Mikir Hills (MH), and Assam syntaxis. Higher velocity indicates an upward buckled crustal structure. The Tibetan plateau has a low velocity, indicating a thick crust and partial melt in the middle to lower crust. The inverted SH wave velocity models also show similar patterns. Based on such analysis, variation in the Moho depth below the study area could be estimated. Moho depth below SP and MH varies from 35 to 45 km. Moho depth below BB varies between ~ 28 to ~ 32 km. The uppermost crust in BB indicates a thick sediment deposit of ~ 15- ~ 20 km. The Moho depth of NE India gradually increases towards the Eastern Himalayas, Lhasa block, and IBR. Steeply dipping Moho below IBR indicates the subduction of the Indian plate below the Burma plate. The Tibet and Lhasa blocks show a crustal thickness of ~ 85 km, which is the maximum compared to other parts of the study area. Highly variable shear wave crustal structures, added with low/high-velocity anomalies at different depths, give new insights into the heterogeneous and complex geotectonics.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"30 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147441286","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}