Journal of Seismology最新文献

{"title":"Source parameters of the moderate-sized (ML 4.9) 2018 Arraiolos, Portugal earthquake and its sequence","authors":"Piedade Wachilala,&nbsp;José Fernando Borges,&nbsp;Bento Caldeira,&nbsp;Mourad Bezzeghoud","doi":"10.1007/s10950-025-10299-8","DOIUrl":"10.1007/s10950-025-10299-8","url":null,"abstract":"<div><p>The Arraiolos zone is one of the most seismically active intraplate regions in mainland Portugal and is characterized by low- to moderate-magnitude events. However, there is a need to analyse the characteristics of the seismic source parameters in this zone, which is crucial for understanding the origin of the zone’s seismicity and gaining insights into the stresses involved in the rupture processes of seismic events. On January 15, 2018, an earthquake of magnitude 4.9 M_L occurred northeast of Arraiolos, near Aldeia da Serra. This event was followed by aftershocks with magnitudes of up to 3.5 (M_L). In the present study, we estimated the source parameters and respective scaling relationships of 82 earthquakes (0.6 ≤ M_L ≤ 4.9) that occurred in the study area following the 2018 Arraiolos earthquake. The source parameters were estimated from the displacement spectra of the P-waves by automatic fitting of the Brune spectral model (ω⁻²). Consequently, the parameters characterizing the seismic source, such as the scalar seismic moment (M₀), moment magnitude (M_w), corner frequency (<span>({f}_{c})</span>), source radius (r_o) and stress drop (Δσ), were determined. The results show that the moment magnitude (M_w) varies between 0.9 and 4.3. The source radii range from 31.5 m to 775.9 m, and the stress drop values (Δσ) range from 0.4 bars to 97.0 bars, with an average of 7.3 bars. Furthermore, most earthquakes occur mainly between 12 and 13 km depth, with a range of stress drop values (including low and high values). The linear relationships between the local and moment magnitudes are consistent. An increasing trend was observed between the source radii and the seismic moments, as expected. It was found that there is no linear correlation between stress drops and seismic moments. This suggests that the dynamic parameters controlling the rupture of larger magnitude earthquakes may be different from those of weaker earthquakes. Studying seismic source parameters in the Arraiolos area is crucial for understanding the seismogenic dynamics, as well as to improve regional hazard assessment.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"677 - 697"},"PeriodicalIF":2.0,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-025-10299-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145164617","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":"Multiscale regionalised Rayleigh-wave group and phase velocity maps for East Asia","authors":"Mei Feng,&nbsp;Meijian An,&nbsp;Hesheng Hou,&nbsp;Rongtao Zhao","doi":"10.1007/s10950-025-10298-9","DOIUrl":"10.1007/s10950-025-10298-9","url":null,"abstract":"<div><p>East Asia comprises multiple tectonic domains and has been the subject of many regional and local broadband seismic investigations in recent years, especially the ChinArray experiments. These studies have improved the overall seismic data coverage for East Asia, although the distribution of data is extremely uneven. While regionalised group or phase velocity dispersion curves from surface-wave tomography are particularly important for deriving deep shear-wave velocities, calibrating phase velocity measurements and joint analyses with other geophysical data, they are normally derived using quadrilateral cells with a fixed latitude and longitude spacing, such that the cell spacing varies with latitude but not with data coverage. For a region with extremely uneven data coverage, closely spaced cells will worsen the ill-posedness of tomographic problems, whereas widely spaced cells will lower the lateral resolution capability of regions with dense data. Here we propose a new model discretisation approach for two-dimensional surface-wave tomography that divides the study area into triangular cells with variable sizes based on data coverage and apply it to East Asia, where seismic observations are numerous but unevenly distributed. The updated regionalised Rayleigh-wave group and phase velocity maps detect small sedimentary basins with low velocities and large cratons with high velocities, implying that our approach can simultaneously image local-, regional- and large-scale structures in one tomographic system. The regionalised dispersion curves can be used to invert for deep structure directly or jointly with other geophysical observations across East Asia.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"661 - 676"},"PeriodicalIF":2.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162521","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":"Earthquake cycle progression in major city regions of Taiwan through nowcasting technique","authors":"Sonu Devi,&nbsp;Sumanta Pasari","doi":"10.1007/s10950-025-10295-y","DOIUrl":"10.1007/s10950-025-10295-y","url":null,"abstract":"<div><p>The complex tectonic framework of Taiwan makes it susceptible to devastating earthquakes that originate on both mapped faults, and at times, on unmapped faults. The unmapped faults especially highlight the limitation of conventional fault–based hazard assessment methods, emphasizing the need for alternative approaches. In this context, we implement a surrogate area–based earthquake nowcasting technique to assess the seismic cycle progression in 10 densely populated cities across Taiwan. We utilize the notion of natural times, the inter–event counts of small earthquakes between successive large events, to calculate the Earthquake Potential Score (EPS) for each city region. To derive natural time statistics, we analyze eight reference probability models, including exponential distribution and its variants, exponentiated group of distributions, and heavy–tailed distributions. Statistical inference of 114 observed natural times shows that the exponentiated exponential distribution provides the best fit. As of April 24, 2025, the EPS values (%) for M <span>(ge )</span> 6.0 earthquakes in the 10 cities range from 53% to 69%, with the following values: Taipei (69%), Hsinchu (68%), Keelung (67%), Hualien (59%), Nantou (58%), Taitung (57%), Chiayi (56%), Pingtung (55%), Tainan (54%), and Kaohsiung (53%). These EPS values indicate the progression in current earthquake cycle toward a M <span>(ge )</span> 6.0 earthquake in the corresponding city region. Moreover, there is a consistency in the nowcast scores despite some variations in threshold magnitudes and city regions. The studied approach and results therein offer valuable insights to decision makers to enhance earthquake preparedness and risk management across Taiwan.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"603 - 623"},"PeriodicalIF":2.0,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171275","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":"Discrimination of natural and nonnatural earthquakes using a vision transformer","authors":"Jindong Song,&nbsp;Shicheng Luan,&nbsp;Jie Shen,&nbsp;Fajun Miao,&nbsp;Shanyou Li,&nbsp;Qiang Ma,&nbsp;Haozhen Dai,&nbsp;Canjin Wu,&nbsp;Qiyang Chen,&nbsp;Jingbao Zhu","doi":"10.1007/s10950-025-10294-z","DOIUrl":"10.1007/s10950-025-10294-z","url":null,"abstract":"<div><p>Rapidly and reliably distinguishing between natural and nonnatural small-scale earthquakes is crucial for earthquake monitoring and seismic activity analyses. In this study, we propose a vision transformer for seismology (SeisViT) to discriminate between natural and non-natural earthquakes. Our SeisViT is based on a vision transformer (ViT) network that introduces a multihead self-attention mechanism, which can effectively capture and focus on important features from seismic waveforms.The SeisViT model processes three-component raw waveforms from a single seismic station, using data collected from natural and nonnatural earthquakes in China. Through a comprehensive evaluation of hyperparameters—including learning rate, number of transformer encoder layers, and patch size-we optimized the SeisViT architecture to achieve maximal performance. Our results demonstrate that the SeisViT model, with a learning rate of 10^-3, six transformer encoder layers, and a patch size of eight, achieves superior accuracy in discriminating natural from nonnatural earthquakes. Compared to conventional models such as multilayer perceptron (MLP), decision tree (DT), random forest (RF), and support vector machine (SVM), the SeisViT model achieved the highest accuracy (90.17%), precision (89.68%), recall (89.90%), and F1 score (89.79%) on the test dataset. These results underscore the potential of the SeisViT model as a significant advancement for earthquake monitoring with promising applications in seismology.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"585 - 601"},"PeriodicalIF":2.0,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145169485","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":"Numerical modelling of the 1996 Nazca Perú earthquake (Mw 7.7) and tsunami","authors":"Cesar Jimenez","doi":"10.1007/s10950-025-10300-4","DOIUrl":"10.1007/s10950-025-10300-4","url":null,"abstract":"<div><p>In this research, we have obtained the slip distribution of the 1996 Nazca earthquake, using a teleseismic waveform inversion method; then, we have conducted the numerical modelling of the tsunami propagation. The results reveal a complex rupture process with a duration around 70 s for a mean rupture velocity of 2.5 km/s. The maximum slip was 2.9 m and the seismic moment was 5<span>(times 10^{20})</span> Nm, equivalent to a moment magnitude of Mw 7.7. The coseismic deformation field, due to the slip distribution obtained in this research, was used to conduct the tsunami numerical modelling of the 1996 Nazca earthquake. The reported uplift in the coast of San Juan de Marcona was 20 cm and the simulated uplift was 26 cm. This earthquake triggered a small tsunami with only local impact. The maximum simulated tsunami high at San Juan de Marcona tidal station was 1.65 m while the reported value was 1.80 m. We suggest that the 1996 Nazca earthquake can be considered as a part of the 1940-2007 central Peru earthquakes series.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"699 - 712"},"PeriodicalIF":2.0,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145170298","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 the Guatemalan earthquake catalog","authors":"Ramiro González-Negreros,&nbsp;Jorge M. Gaspar-Escribano","doi":"10.1007/s10950-025-10293-0","DOIUrl":"10.1007/s10950-025-10293-0","url":null,"abstract":"<div><p>In this paper, we study the geographic and temporal distribution of earthquakes in Guatemala, and their magnitudes, from 1526 to October 2022. We utilized the earthquake catalog of the national seismic network of Guatemala, complemented by two additional sources. First, we describe the development of the detection network and the seismic catalog. Second, we analyze the errors in the catalog and determine the quality of the focal locations, examining their distribution in time and space while separating events into shallow and deep earthquakes. Finally, we calculate seismic parameters such as annual rates of earthquakes and magnitude of completeness. The results indicate a strong variability in time and space of errors and seismic parameters that are linked to changes in the detection network. In conclusion, by highlighting the evolution of this catalog and its features, this paper underscores the importance of considering these spatial and temporal variations in future analyses of seismicity and seismic hazard in Guatemala. This topic can be of interest to other countries with similar characteristics in tectonics and detection networks.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"565 - 583"},"PeriodicalIF":2.0,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-025-10293-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145169787","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":"Investigation of hydraulic fracturing-induced seismicity in the Haynesville Shale","authors":"James P. Verdon,&nbsp;Alexander D. G. Harris","doi":"10.1007/s10950-025-10296-x","DOIUrl":"10.1007/s10950-025-10296-x","url":null,"abstract":"<div><p>The Haynesville Shale in eastern Texas and western Louisiana has been one of the most productive shale gas plays in the USA. It is notable for being significantly over-pressured, a factor which has often been associated with an increased likelihood of hydraulic fracturing-induced seismicity (HF-IS) elsewhere. However, to date, only one case of HF-IS has been identified in the Haynesville play. Seismic monitoring across the play is relatively sparse, so it is possible that the absence of reported cases represents an absence of monitoring rather than an absence of cases. This study represents an investigation of HF-IS across the Haynesville play, primarily using data from the TexNet seismic monitoring array, which was installed in 2017. We use template matching to increase the population of detected earthquakes, increasing the number of detections by over 200% compared to the catalogs available from regional monitoring agencies. The resulting events can be clustered into several discrete sequences. We use an induced seismicity assessment framework to evaluate whether each sequence was induced and, if so, what industrial activity represents the most likely cause (both hydraulic fracturing and wastewater disposal operations take place within the footprint of the Haynesville play). We find three notable cases of HF-IS, straddling the region between Nacogdoches, San Augustine and Shelby Counties. Having identified these sequences, we examine whether any geological conditions may influence the occurrence of HF-IS. We identify increased formation depth, increased pore pressure gradients, and the thinning or absence of the underlying Louann Salt, which may otherwise serve as a hydraulic barrier between the Haynesville Shale and the basement, as factors that may account for the varying prevalence of HF-IS across the play.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"625 - 641"},"PeriodicalIF":2.0,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12271280/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144675066","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":"Estimating dynamic source parameters from S-Wave spectra for earthquakes in the Dahshour Region, Northwestern Egypt","authors":"Hamada Saadalla,&nbsp;Saleh Qaysi,&nbsp;Mohamed Ezzelarab,&nbsp;Abdalla Abdelnabi,&nbsp;Turki Sehli","doi":"10.1007/s10950-025-10297-w","DOIUrl":"10.1007/s10950-025-10297-w","url":null,"abstract":"<div><p>This study analyzes the dynamic source parameters of S-wave displacement spectra for 104 seismic events (1.7 ≤ <span>({M}_{L})</span>  ≤ 3.6) recorded by the Egyptian National Seismic Network (ENSN) between 2010 and 2024 in the Dahshour region, northwestern Egypt. The Generalized Inversion Technique (GIT) was employed to correct the source displacement spectra for receiver and path effects using a linear least-squares approach, assuming a reference site. Two seismic stations that belong to ENSN namely, New Bani Suef (NBNS) and New Katemiya (NKOT), were utilized as a reference site in the inversion analysis. Attenuation effects along the ray path and site-specific influences were removed to derive source spectra at each station. The averaged S-wave source spectrum deviates from the Brune ω² source model. Key spectral parameters, including long-period amplitude (Ω₀) and corner frequency (<span>({f}_{C})</span>), were determined, allowing for the estimation of source parameters. Corner frequency, Seismic moment, fault radius, and stress drop were calculated from the corrected displacement spectra. The S-wave displacement spectra exhibited a rapid decay at 10 Hz within the analyzed frequency range (0.8–50 Hz). For NBNS (reference site), the estimated corner frequency, seismic moment, source radius, and stress drop ranged from 2.6 to 9.6 Hz, 8.7 × 10¹⁸ to 1.2 × 10²¹ dyne-cm, 78.9 to 292.3 m, and 0.04 to 10.13 MPa, respectively. For NKOT, these values ranged from 2.8 to 9.9 Hz, 1.26 × 10¹⁹ to 1.58 × 10²¹ dyne-cm, 76.1 to 273.3 m, and 0.2 to 16.13 MPa, respectively. These results provide insights into the seismic source characteristics of the Dahshour region, contributing to a better understanding of earthquake dynamics, crucial for characterizing the energy release and rupture mechanisms of earthquakes in northwestern Egypt.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"643 - 659"},"PeriodicalIF":2.0,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145166704","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":"The hypothesis of the 1513/1514 very large earthquake in the East Anatolian Fault Zone: rise and weakness","authors":"Viviana Castelli,&nbsp;Massimiliano Stucchi","doi":"10.1007/s10950-025-10292-1","DOIUrl":"10.1007/s10950-025-10292-1","url":null,"abstract":"<div><p>Most of the scientific literature on the Eastern Anatolian Fault Zone (EAFZ) mentions a very large earthquake occurring in 1513 or 1514, presumably in the Pazarcik segment. This earthquake could play an important role in the assessment of the EAFZ seismogenic potential, provided its parameters were reliable. However, these parameters have a flimsy historical basis: just a few words of a letter sent from Damascus to Venice in March 1514, reporting severe damage in three towns in south-eastern Anatolia, one of which is hundreds kilometres away from the other two. Despite extensive research into contemporary and later historical sources and the history of monumental buildings of the three towns, we have found no evidence of damage/restoration to monuments predating 1513/1514 in the affected sites. Nor are there mentions of earthquake effects elsewhere in Anatolia and surrounding countries. Contemporary reports—mostly concerned with the 1514/1517 wars between the Ottoman, Safavid and Mamluk empires—make no mention of this earthquake or of any hindrances which its aftermath might have caused to troops marching through the allegedly devastated region (e.g. with regard to procuring supplies and shelter, or to travel difficulties due to damage to road infrastructures, landslides and the like). At the current state of knowledge, we suggest that the only available earthquake description may be either unwittingly overestimated, or possibly a conflation of two smaller earthquakes, with different epicentral locations.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"553 - 564"},"PeriodicalIF":2.0,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-025-10292-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145169719","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 23 and 24 January 2022 Tabriz (Northwestern Iran) small earthquakes: Seismological study and seismotectonic implication","authors":"Saeid Rahimzadeh,&nbsp;Behnam M. Asayesh,&nbsp;Noorbakhsh Mirzaei,&nbsp;Mehrdad Pakzad","doi":"10.1007/s10950-025-10290-3","DOIUrl":"10.1007/s10950-025-10290-3","url":null,"abstract":"<div><p>This study analyzes the characteristics of the January 23 and 24, 2022, Tabriz earthquakes in northwestern Iran. These events, with magnitudes of <span>(M_w)</span> 4.2 and <span>(M_w)</span> 4.0, occurred within the Tabriz pull-apart basin and represent the largest seismic occurrences in the region over the past two centuries. Focal mechanism solutions indicate strike-slip faulting for the first event and normal faulting with a strike-slip component for the second event. Both events occurred on NW-trending faults. Based on recorded ground motion data, the first event ruptured in the NW direction, while the second event ruptured in the opposite direction (SE). Coulomb stress changes analysis suggests that stress changes imparted by the first event, estimated about 0.1 bar at the hypocenter of the second event, likely promoted its triggering. These findings highlight the active tectonics of the Tabriz Basin and the significant seismic hazards posed by its active faults, particularly for the city of Tabriz, which has a population over 2 million and is situated within the basin.</p></div>","PeriodicalId":16994,"journal":{"name":"Journal of Seismology","volume":"29 3","pages":"535 - 552"},"PeriodicalIF":2.0,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10950-025-10290-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168501","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}