Pub Date : 2025-01-01DOI: 10.1016/j.eqrea.2024.100315
Ayaz Mohmood Dar, Syed Kaiser Bukhari
The Kashmir Basin, shaped by the collision of the Indian and Eurasian tectonic plates, features prominent faults, including the Balapur fault and other fault zones. This study focuses on the Gulmarg fault within the Northwestern Himalaya, using advanced geomagnetic techniques for delineation. Geomagnetic measurements reveal the characteristics of the newly identified Gulmarg fault. Ground magnetic surveys with Proton Precession Magnetometers along linear profiles and a magnetic grid highlight fault-related anomalies. The results indicate a fault running through the Gulmarg meadows, approximately 1.6 km from the Balapur fault, suggesting a potential coupling between the two. Three profiles across the fault exhibit distinctive magnetic variations, highlighting the intricate nature of the fault structure. Gridding methods also reveal anomalies associated with subsurface water and hydraulic activities, underscoring the importance of advanced geophysical techniques. This study emphasizes the significance of detailed investigations to unravel the complex geological processes shaping the Kashmir Basin. The study provides valuable insights into the tectonic activity in the Gulmarg region, underscoring the role of geophysical studies in enhancing our understanding of dynamic geological structures like the Gulmarg fault zone.
{"title":"Geophysical delineation of the newly identified Gulmarg fault in the Kashmir Basin, NW Himalaya. Implications for active structural control","authors":"Ayaz Mohmood Dar, Syed Kaiser Bukhari","doi":"10.1016/j.eqrea.2024.100315","DOIUrl":"10.1016/j.eqrea.2024.100315","url":null,"abstract":"<div><div>The Kashmir Basin, shaped by the collision of the Indian and Eurasian tectonic plates, features prominent faults, including the Balapur fault and other fault zones. This study focuses on the Gulmarg fault within the Northwestern Himalaya, using advanced geomagnetic techniques for delineation. Geomagnetic measurements reveal the characteristics of the newly identified Gulmarg fault. Ground magnetic surveys with Proton Precession Magnetometers along linear profiles and a magnetic grid highlight fault-related anomalies. The results indicate a fault running through the Gulmarg meadows, approximately 1.6 km from the Balapur fault, suggesting a potential coupling between the two. Three profiles across the fault exhibit distinctive magnetic variations, highlighting the intricate nature of the fault structure. Gridding methods also reveal anomalies associated with subsurface water and hydraulic activities, underscoring the importance of advanced geophysical techniques. This study emphasizes the significance of detailed investigations to unravel the complex geological processes shaping the Kashmir Basin. The study provides valuable insights into the tectonic activity in the Gulmarg region, underscoring the role of geophysical studies in enhancing our understanding of dynamic geological structures like the Gulmarg fault zone.</div></div>","PeriodicalId":100384,"journal":{"name":"Earthquake Research Advances","volume":"5 1","pages":"Article 100315"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.eqrea.2024.100328
Jiangtao Qiu , Lingyun Ji , Liangyu Zhu , Yongsheng Li , Chuanjin Liu , Qiang Zhao
On April 3, 2024, an M7.3 earthquake occurred in the offshore area of Hualien County, Taiwan, China. The seismogenic structure at the epicentral location was highly complex, and studying this earthquake is paramount for understanding regional fault activity. In this study, we employed ascending and descending orbit Sentinel-1 Synthetic Aperture Radar (SAR) data and utilized differential interferometry (InSAR) technique to obtain the co-seismic deformation field of this event. The line-of-sight deformation field revealed that the main deformation caused by this earthquake was predominantly uplift, with maximum uplift values of approximately 38.8 cm and 46.1 cm for the ascending and descending orbits, respectively. By integrating the three-dimensional GNSS co-seismic deformation field, we identified the seismogenic fault located in the offshore thrust zone east of Hualien, trending towards the northwest. The fault geometry parameters, obtained through the inversion of an elastic half-space homogeneous model, indicated an optimal fault strike of 196°, a dip angle of 30.9°, and an average strike-slip of 0.4 m and dip-slip of −2.6 m. This suggests that the predominant motion along the seismogenic fault is thrusting. The distribution of post-seismic Coulomb stress changes revealed that aftershocks mainly occurred in stress-loaded regions. However, stress loading was observed along the northern segment of the Longitudinal Valley Fault, with fewer aftershocks. This highlights the importance of closely monitoring the seismic hazard associated with this fault segment.
{"title":"Coseismic deformation and seismogenic structure of the 2024 Hualien Earthquake measured by InSAR and GNSS","authors":"Jiangtao Qiu , Lingyun Ji , Liangyu Zhu , Yongsheng Li , Chuanjin Liu , Qiang Zhao","doi":"10.1016/j.eqrea.2024.100328","DOIUrl":"10.1016/j.eqrea.2024.100328","url":null,"abstract":"<div><div>On April 3, 2024, an <em>M</em>7.3 earthquake occurred in the offshore area of Hualien County, Taiwan, China. The seismogenic structure at the epicentral location was highly complex, and studying this earthquake is paramount for understanding regional fault activity. In this study, we employed ascending and descending orbit Sentinel-1 Synthetic Aperture Radar (SAR) data and utilized differential interferometry (InSAR) technique to obtain the co-seismic deformation field of this event. The line-of-sight deformation field revealed that the main deformation caused by this earthquake was predominantly uplift, with maximum uplift values of approximately 38.8 cm and 46.1 cm for the ascending and descending orbits, respectively. By integrating the three-dimensional GNSS co-seismic deformation field, we identified the seismogenic fault located in the offshore thrust zone east of Hualien, trending towards the northwest. The fault geometry parameters, obtained through the inversion of an elastic half-space homogeneous model, indicated an optimal fault strike of 196°, a dip angle of 30.9°, and an average strike-slip of 0.4 m and dip-slip of −2.6 m. This suggests that the predominant motion along the seismogenic fault is thrusting. The distribution of post-seismic Coulomb stress changes revealed that aftershocks mainly occurred in stress-loaded regions. However, stress loading was observed along the northern segment of the Longitudinal Valley Fault, with fewer aftershocks. This highlights the importance of closely monitoring the seismic hazard associated with this fault segment.</div></div>","PeriodicalId":100384,"journal":{"name":"Earthquake Research Advances","volume":"5 1","pages":"Article 100328"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.eqrea.2024.100329
Mengjie Yang , Shenghua Cui , Tao Jiang
Earthquake-induced landslides have always been a hot research topic in the field of geosciences. However, there have been few bibliometric analyses on this topic. To systematically understand the research status, this study is based on bibliometrics and extensively uses visualization analysis techniques. It combines quantitative and qualitative methods to conduct an in-depth analysis of 5 016 papers collected from the Web of Science (www.webofscience.com). The results revealed that: ①The number of papers on earthquake-induced landslides is steadily increasing, and is expected to continue to rise. ②Countries prone to frequent earthquakes have made significant contributions to the research on earthquake-induced landslides, and the frequent and effective cooperation among these countries has had a very positive impact on promoting landslide study. ③ Research on earthquake-induced landslides is no longer limited to the field of geology, and the future direction is to integrate knowledge and technical methods from multiple disciplines. In the research methods of earthquake-induced landslides, there is a gradual shift from "experience, theory" to "data-driven". This study can provide researchers in this field with information on the core research forces, evolving hot topics, and future development trends of earthquake-induced landslides.
地震诱发滑坡一直是地学领域的研究热点。然而，关于这一主题的文献计量分析很少。为了系统地了解研究现状，本研究以文献计量学为基础，广泛使用可视化分析技术。它结合了定量和定性方法，对从Web of Science （www.webofscience.com）收集的5016篇论文进行了深入分析。结果表明：①关于地震诱发滑坡的论文数量稳步增加，并有望继续增加。②地震多发国家对地震诱发滑坡的研究做出了重要贡献，这些国家之间频繁而有效的合作对促进滑坡研究产生了非常积极的影响。③地震诱发滑坡的研究已不再局限于地质领域，未来的发展方向是多学科知识和技术方法的整合。在地震诱发滑坡的研究方法上，逐渐从“经验、理论”转向“数据驱动”。通过本研究，可以了解地震诱发滑坡的核心研究力量、发展热点和未来发展趋势。
{"title":"Global research trends in seismic landslide: A bibliometric analysis","authors":"Mengjie Yang , Shenghua Cui , Tao Jiang","doi":"10.1016/j.eqrea.2024.100329","DOIUrl":"10.1016/j.eqrea.2024.100329","url":null,"abstract":"<div><div>Earthquake-induced landslides have always been a hot research topic in the field of geosciences. However, there have been few bibliometric analyses on this topic. To systematically understand the research status, this study is based on bibliometrics and extensively uses visualization analysis techniques. It combines quantitative and qualitative methods to conduct an in-depth analysis of 5 016 papers collected from the Web of Science (<span><span>www.webofscience.com</span><svg><path></path></svg></span>). The results revealed that: ①The number of papers on earthquake-induced landslides is steadily increasing, and is expected to continue to rise. ②Countries prone to frequent earthquakes have made significant contributions to the research on earthquake-induced landslides, and the frequent and effective cooperation among these countries has had a very positive impact on promoting landslide study. ③ Research on earthquake-induced landslides is no longer limited to the field of geology, and the future direction is to integrate knowledge and technical methods from multiple disciplines. In the research methods of earthquake-induced landslides, there is a gradual shift from \"experience, theory\" to \"data-driven\". This study can provide researchers in this field with information on the core research forces, evolving hot topics, and future development trends of earthquake-induced landslides.</div></div>","PeriodicalId":100384,"journal":{"name":"Earthquake Research Advances","volume":"5 1","pages":"Article 100329"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.eqrea.2024.100333
Zhigao Yang , Huifang Chen
The Hualien M 7.3 earthquake on April 3, 2024, was a significant and strong earthquake in Taiwan, China in the past two decades. The rupture process of the main shock and strong aftershocks is of great significance to the subsequent seismic activity and seismogenic tectonic research. Based on local strong-motion data, we used the IDS (Iterative Deconvolution and Stacking) method to obtain the rupture process of the mainshock and two strong aftershocks on the 23rd. The rupture of the mainshock was mainly unilateral, lasting 31 s, with a maximum slip of 2 m, and the depth of the large slip zone is about 41–49 km. There is a clear difference between the rupture depth of the main shock and the two strong aftershocks. The depths of the large slip zones of the latter two are 3–9 km and 8–10 km, respectively. There is also a significant difference in the seismogenic fault between the mainshock and the aftershocks, and we believe that there are two seismogenic fault zones in the study area, the deep and the shallow fault zone. The slip of the deep faults activates the shallow faults.
{"title":"The rupture process of the Hualien M7.3 sequence on April 3, 2024","authors":"Zhigao Yang , Huifang Chen","doi":"10.1016/j.eqrea.2024.100333","DOIUrl":"10.1016/j.eqrea.2024.100333","url":null,"abstract":"<div><div>The Hualien <em>M</em> 7.3 earthquake on April 3, 2024, was a significant and strong earthquake in Taiwan, China in the past two decades. The rupture process of the main shock and strong aftershocks is of great significance to the subsequent seismic activity and seismogenic tectonic research. Based on local strong-motion data, we used the IDS (Iterative Deconvolution and Stacking) method to obtain the rupture process of the mainshock and two strong aftershocks on the 23rd. The rupture of the mainshock was mainly unilateral, lasting 31 s, with a maximum slip of 2 m, and the depth of the large slip zone is about 41–49 km. There is a clear difference between the rupture depth of the main shock and the two strong aftershocks. The depths of the large slip zones of the latter two are 3–9 km and 8–10 km, respectively. There is also a significant difference in the seismogenic fault between the mainshock and the aftershocks, and we believe that there are two seismogenic fault zones in the study area, the deep and the shallow fault zone. The slip of the deep faults activates the shallow faults.</div></div>","PeriodicalId":100384,"journal":{"name":"Earthquake Research Advances","volume":"5 1","pages":"Article 100333"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143135630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.eqrea.2024.100311
Submarine seismic ambient noise imaging combines current marine and on-land seismic detection technologies. Based on data from several broadband shallow-sea type ocean bottom seismometers (SOBSs) deployed in the Bohai Sea and north Yellow Sea, this paper analyzes the submarine seismic ambient noise characteristics. It explores the theory, technology, method and application of the submarine seismic ambient noise imaging using the single-point horizontal and vertical spectral ratio method (HVSR). The observations yield the following results: 1) Submarine seismic ambient noise has consistent and constant energy, making it an appropriate passive seismic source for submarine high-frequency surface wave investigation. 2) Using the HVSR approach, a single three-component OBS could differentiate between the basement and sediments. Array seismic observation could be utilized to extract the frequency dispersion curve and invert it to obtain the velocity structure for more accurate stratification. 3) The SOBS we use is suitable for submarine surface wave exploration. 4) Tomography results with greater resolution and deeper penetration could be obtained by combining active and passive sources in a simultaneous inversion of the HVSR and frequency dispersion curve. Seamless land-to-ocean seismic research can be accomplished with submarine seismic ambient noise imaging technologies.
{"title":"Characterization and application of submarine seismic ambient noise in the Bohai Sea and Yellow Sea","authors":"","doi":"10.1016/j.eqrea.2024.100311","DOIUrl":"10.1016/j.eqrea.2024.100311","url":null,"abstract":"<div><div>Submarine seismic ambient noise imaging combines current marine and on-land seismic detection technologies. Based on data from several broadband shallow-sea type ocean bottom seismometers (SOBSs) deployed in the Bohai Sea and north Yellow Sea, this paper analyzes the submarine seismic ambient noise characteristics. It explores the theory, technology, method and application of the submarine seismic ambient noise imaging using the single-point horizontal and vertical spectral ratio method (HVSR). The observations yield the following results: 1) Submarine seismic ambient noise has consistent and constant energy, making it an appropriate passive seismic source for submarine high-frequency surface wave investigation. 2) Using the HVSR approach, a single three-component OBS could differentiate between the basement and sediments. Array seismic observation could be utilized to extract the frequency dispersion curve and invert it to obtain the velocity structure for more accurate stratification. 3) The SOBS we use is suitable for submarine surface wave exploration. 4) Tomography results with greater resolution and deeper penetration could be obtained by combining active and passive sources in a simultaneous inversion of the HVSR and frequency dispersion curve. Seamless land-to-ocean seismic research can be accomplished with submarine seismic ambient noise imaging technologies.</div></div>","PeriodicalId":100384,"journal":{"name":"Earthquake Research Advances","volume":"4 4","pages":"Article 100311"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141036524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.eqrea.2024.100327
Jing Wang , Huajian Yao , Ying Liu , Baoshan Wang , Weitao Wang
The Binchuan Basin in northwest Yunnan, southwest China, is a rift basin developed at the intersection of the Red River Fault and Chenghai Fault, where historical earthquakes have occurred. Understanding the fine velocity structure of the shallow crust in this region can help improve earthquake location accuracy and our understanding of the relationship between fault zone structures and fault slip behaviors. Using the continuous waveform data recorded by 381 dense array stations in 2017, we obtained 7 915 Rayleigh-wave phase velocity dispersion curves in the period band of 0.2–6 s from ambient noise cross-correlation functions after rigorous data processing and quality control. We determined 3D isotropic and azimuthally anisotropic shear wave velocity models at depths above 6 km in the shallow crust based on the direct surface wave azimuthal anisotropic tomography method. The isotropic model reveals a strong correspondence between the S-wave velocity structure at depths of 0–1 km and the regional topography and lithology. The Binchuan depocenter, Zhoucheng depocenter, Xiangyun Basin, and Xihai Rift Basin are primarily composed of Quaternary deposits, which show low-velocity anomalies, while the regions with the Paleozoic shale, limestone, and basalt exhibit high-velocity anomalies. The nearly N–S orientation of fast directions from azimuthal anisotropy models are mainly controlled by the active Binchuan Fault with N–S strike as well as the NNW-oriented primary compressive stress.
{"title":"3D shear wave velocity and azimuthal anisotropy structure in the shallow crust of Binchuan Basin in Yunnan, Southwest China, from ambient noise tomography","authors":"Jing Wang , Huajian Yao , Ying Liu , Baoshan Wang , Weitao Wang","doi":"10.1016/j.eqrea.2024.100327","DOIUrl":"10.1016/j.eqrea.2024.100327","url":null,"abstract":"<div><div>The Binchuan Basin in northwest Yunnan, southwest China, is a rift basin developed at the intersection of the Red River Fault and Chenghai Fault, where historical earthquakes have occurred. Understanding the fine velocity structure of the shallow crust in this region can help improve earthquake location accuracy and our understanding of the relationship between fault zone structures and fault slip behaviors. Using the continuous waveform data recorded by 381 dense array stations in 2017, we obtained 7 915 Rayleigh-wave phase velocity dispersion curves in the period band of 0.2–6 s from ambient noise cross-correlation functions after rigorous data processing and quality control. We determined 3D isotropic and azimuthally anisotropic shear wave velocity models at depths above 6 km in the shallow crust based on the direct surface wave azimuthal anisotropic tomography method. The isotropic model reveals a strong correspondence between the S-wave velocity structure at depths of 0–1 km and the regional topography and lithology. The Binchuan depocenter, Zhoucheng depocenter, Xiangyun Basin, and Xihai Rift Basin are primarily composed of Quaternary deposits, which show low-velocity anomalies, while the regions with the Paleozoic shale, limestone, and basalt exhibit high-velocity anomalies. The nearly N–S orientation of fast directions from azimuthal anisotropy models are mainly controlled by the active Binchuan Fault with N–S strike as well as the NNW-oriented primary compressive stress.</div></div>","PeriodicalId":100384,"journal":{"name":"Earthquake Research Advances","volume":"4 4","pages":"Article 100327"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141706801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.eqrea.2024.100312
The 2024 Noto Peninsula Earthquake was a significant seismic event that caused extensive damage across the region, characterized by a strong shake, subsequent tsunami, fires, liquefaction, and landslides. An emergency survey was conducted by our team from January 6 to January 8, 2024, focusing primarily on the impact of the earthquake on road bridges. This preliminary report includes ground motion records from the most affected areas and their response spectra, providing insights into the earthquake's intensity and characteristics. Among the key findings, substantial damage was reported to the long-span bridges connecting Noto Island to the mainland, specifically the Noto Island Ohashi Bridge and the Naka-Noto Agriculture Bridge (Twin Bridge Noto). These bridges are crucial as they serve as the sole access points to Noto Island. Additionally, the survey recorded damage to several other structures, including the Okogawa Bridges, Ouchigata Bridge, and a collapsed old wooden bridge.
{"title":"A fast survey report about bridge damages by the 2024 Noto Peninsula Earthquake","authors":"","doi":"10.1016/j.eqrea.2024.100312","DOIUrl":"10.1016/j.eqrea.2024.100312","url":null,"abstract":"<div><div>The 2024 Noto Peninsula Earthquake was a significant seismic event that caused extensive damage across the region, characterized by a strong shake, subsequent tsunami, fires, liquefaction, and landslides. An emergency survey was conducted by our team from January 6 to January 8, 2024, focusing primarily on the impact of the earthquake on road bridges. This preliminary report includes ground motion records from the most affected areas and their response spectra, providing insights into the earthquake's intensity and characteristics. Among the key findings, substantial damage was reported to the long-span bridges connecting Noto Island to the mainland, specifically the Noto Island Ohashi Bridge and the Naka-Noto Agriculture Bridge (Twin Bridge Noto). These bridges are crucial as they serve as the sole access points to Noto Island. Additionally, the survey recorded damage to several other structures, including the Okogawa Bridges, Ouchigata Bridge, and a collapsed old wooden bridge.</div></div>","PeriodicalId":100384,"journal":{"name":"Earthquake Research Advances","volume":"4 4","pages":"Article 100312"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141057637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.eqrea.2024.100310
In this study, we swiftly determined the focal parameters (focal mechanism, seismic imaging process, magnitude) of the Jishishan earthquake, leveraging a solved fault model to assess the intensity field and casualties promptly. The investigation began by retrieving the source mechanism through the P-wave initial motion and W-phase method. This enabled us to chart the spatial and temporal distribution of energy release in the source area via the back-projection technique. Following this, we estimated the earthquake's intensity field by merging the source inversion findings with the ground motion prediction equation. This analysis facilitated the evaluation of earthquake casualties, utilizing the theoretical intensity field and a casualty assessment model. Our findings indicate that the fault type is a thrust fault, characterized by a unilateral rupture in the direction of NW, with a rupture length spanning approximately 10–15 km and a duration ranging between 8 and 10 s. The earthquake's magnitude varied from M 5.9 to M 6.2. The demarcated high-intensity areas, as per our intensity assessment, align closely with the actual survey results. Furthermore, the predicted total casualties and identified critical rescue zones closely match the real-world casualty figures. These insights offer crucial technical support for governmental emergency command and rescue operations.
在本研究中，我们迅速确定了积石山地震的震源参数（震源机制、地震成像过程、震级），并利用已解决的断层模型及时评估了烈度场和人员伤亡情况。调查首先通过 P 波初动和 W 相法检索震源机制。这使我们能够通过反投影技术绘制出震源区能量释放的时空分布图。随后，我们将震源反演结果与地动预测方程相结合，估算了地震烈度场。这项分析有助于利用理论烈度场和伤亡评估模型对地震伤亡进行评估。我们的研究结果表明，该断层类型为推断断层，其特点是向西北方向单侧断裂，断裂长度约为 10-15 千米，持续时间为 8-10 秒。地震震级为 5.9 级至 6.2 级。根据我们的烈度评估，划定的高烈度地区与实际调查结果非常吻合。此外，预测的总伤亡人数和确定的关键救援区域也与实际伤亡数字非常吻合。这些见解为政府应急指挥和救援行动提供了重要的技术支持。
{"title":"Rapid determination of source parameters of the M6.2 Jishishan earthquake in Gansu Province and its application in emergency response","authors":"","doi":"10.1016/j.eqrea.2024.100310","DOIUrl":"10.1016/j.eqrea.2024.100310","url":null,"abstract":"<div><div>In this study, we swiftly determined the focal parameters (focal mechanism, seismic imaging process, magnitude) of the Jishishan earthquake, leveraging a solved fault model to assess the intensity field and casualties promptly. The investigation began by retrieving the source mechanism through the P-wave initial motion and W-phase method. This enabled us to chart the spatial and temporal distribution of energy release in the source area via the back-projection technique. Following this, we estimated the earthquake's intensity field by merging the source inversion findings with the ground motion prediction equation. This analysis facilitated the evaluation of earthquake casualties, utilizing the theoretical intensity field and a casualty assessment model. Our findings indicate that the fault type is a thrust fault, characterized by a unilateral rupture in the direction of NW, with a rupture length spanning approximately 10–15 km and a duration ranging between 8 and 10 s. The earthquake's magnitude varied from <em>M</em> 5.9 to <em>M</em> 6.2. The demarcated high-intensity areas, as per our intensity assessment, align closely with the actual survey results. Furthermore, the predicted total casualties and identified critical rescue zones closely match the real-world casualty figures. These insights offer crucial technical support for governmental emergency command and rescue operations.</div></div>","PeriodicalId":100384,"journal":{"name":"Earthquake Research Advances","volume":"4 4","pages":"Article 100310"},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141037375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.eqrea.2024.100294
The site effect is a crucial factor when analyzing seismic risk and establishing ground motion attenuation relationships. A number of countries have introduced building site classification into earthquake-resistant design codes to account for local site effects on ground motion. However, most site classification indicators rely on drilling data, which is often expensive and requires considerable manpower. As a result, the less detailed drilling data may lead to an undetermined site category of numerous stations. In this study, a Support Vector Machine (SVM) algorithm-based site classification model was trained to address this issue using strong ground motion data and site data from KiK-net and K-net. The classification model used the average HVSR curve of the labeled site and the combined inputs, including frequency, peak, “prominence, and “sharpness” extracted from the curve. The SVM classification model has an accuracy of 76.12% on the test set, with recall rates of 82.69%, 75%, and 63.64% for sites I, II, and III, respectively. The precision rates are 75.44%, 73.77%, and 87.50%, respectively, with F1 scores of 78.90%, 74.38%, and 73.68%. For sites without significant peaks in the HVSR curve, the HVSR curve value was used as the characteristic parameter (input), and the SVM-based site classification model was also trained. The accuracy of class I and II is 75.86%. The results of this study show higher recall and accuracy rates than those obtained using the spectral ratio curve matching method and GRNN method, indicating a better classification performance. Finally, the generalization ability of the model was verified using some basic stations in Xinjiang deployed by the “National Seismic Intensity Rapid Reporting and Early Warning Project”. The SVM-based site classification model that employs strong motion data can provide more reliable classification results for sites without detailed borehole information, and the site classification results can serve as a reference for probing ground motion attenuation relationships, ground motion simulation, and seismic fortification considering the site effect.
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Pub Date : 2024-10-01DOI: 10.1016/j.eqrea.2024.100309
When inverting the S-wave velocity and azimuthal anisotropy from ambient noise data, it is always to obtain the partial overlapped inversion results in contiguous different regions. Merging different data to achieve a consistent model becomes an essential requirement. Based on the S-wave velocity and azimuthal anisotropy obtained from different contiguous regions, this paper introduces three kinds of methods for merging data. For data from different regions with partial overlapping areas, the merged results could be calculated by direct average weighting (DAW), linear dynamic weighting (LDW), and Gaussian function weighting (GFW), respectively. Data tests demonstrate that the LDW and GFW methods can effectively merge data by reasonably allocating data weights to capitalize on the data quality advantages in each zone. In particular, they can resolve the data smoothness at the boundaries of data areas, resulting in a consistent data model in larger regions. This paper presents the effective methods and valuable experiences that can be referred to as advancing data merging technology.
从环境噪声数据反演 S 波速度和方位各向异性时，总是要在连续的不同区域获得部分重叠的反演结果。合并不同数据以获得一致的模型成为一项基本要求。基于从不同连续区域获得的 S 波速度和方位各向异性，本文介绍了三种合并数据的方法。对于部分重叠区域的不同区域数据，可分别采用直接平均加权法（DAW）、线性动态加权法（LDW）和高斯函数加权法（GFW）计算合并结果。数据测试表明，线性动态加权法和高斯函数加权法通过合理分配数据权重，充分利用各区的数据质量优势，可以有效地合并数据。特别是，它们可以解决数据区域边界的数据平滑问题，从而在更大的区域内形成一致的数据模型。本文介绍了这些有效的方法和宝贵的经验，可谓数据合并技术的进步。
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