Pub Date : 2025-12-01DOI: 10.1016/j.eqs.2025.08.002
Jiang Cheng, Hua Pan, Changlong Li, Yao-Hu Zhang
In this study, a seismic hazard algorithm was developed, coupled with a multi-source model. The algorithm can calculate the seismic hazard of 2D planar sources and 3D fault sources. A point source model is used to calculate the 2D planar potential seismic source by discretizing the potential seismic source into grid points which represent seismic sources. In contrast, a rupture surface model is used to calculate the 3D fault source so as to account for the influence of rupture scale in large earthquakes. The corresponding computational software was developed in Java and was tested on a study area 39.2°N–40.4°N and 116.6°E–118.7°E; the Tangshan and Xiadian faults were used to construct the fault source. Compared with the hazard results obtained using a point source model to calculate a 2D planar potential seismic source, the hazard results will be higher when a rupture surface model is used to calculate a 3D fault source. Moreover, a lower exceedance probability corresponds to a greater contribution rate of the fault source to the hazard and a greater seismic hazard closer to the fault. The algorithm can be used for seismic hazard analysis and can serve as a reference for the development of next-generation methods for zoning areas based on seismic ground motion.
{"title":"A fault source-based algorithm for probabilistic analysis of seismic hazard incorporating the rupture scale of large earthquakes","authors":"Jiang Cheng, Hua Pan, Changlong Li, Yao-Hu Zhang","doi":"10.1016/j.eqs.2025.08.002","DOIUrl":"10.1016/j.eqs.2025.08.002","url":null,"abstract":"<div><div>In this study, a seismic hazard algorithm was developed, coupled with a multi-source model. The algorithm can calculate the seismic hazard of 2D planar sources and 3D fault sources. A point source model is used to calculate the 2D planar potential seismic source by discretizing the potential seismic source into grid points which represent seismic sources. In contrast, a rupture surface model is used to calculate the 3D fault source so as to account for the influence of rupture scale in large earthquakes. The corresponding computational software was developed in Java and was tested on a study area 39.2°N–40.4°N and 116.6°E–118.7°E; the Tangshan and Xiadian faults were used to construct the fault source. Compared with the hazard results obtained using a point source model to calculate a 2D planar potential seismic source, the hazard results will be higher when a rupture surface model is used to calculate a 3D fault source. Moreover, a lower exceedance probability corresponds to a greater contribution rate of the fault source to the hazard and a greater seismic hazard closer to the fault. The algorithm can be used for seismic hazard analysis and can serve as a reference for the development of next-generation methods for zoning areas based on seismic ground motion.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 6","pages":"Pages 575-589"},"PeriodicalIF":4.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719032","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}
Pub Date : 2025-12-01DOI: 10.1016/j.eqs.2025.02.002
Yixiao Zhang, Ruifeng Liu, Zibo Wang, Zan Li
Radiated seismic energy is a quantitative characteristic of an earthquake that depends not only on the initial and final stresses, but also on the rupture history, and reflects the dynamic characteristics of the source. The seismic wave energy radiated per unit of seismic moment, or energy-moment ratio, represents the balance between the stress drop, source rupture velocity, and variation in the shear wave velocity. Earthquakes with a high energy-moment ratio thus release strain energy more rapidly. The accurate and rapid determination of radiated seismic energy and the energy-moment ratio play an important role in seismic hazard assessment, quantitative earthquake research, and engineering seismology research. In this study, waveform data from the Global Seismographic Network were used to measure the dynamic source parameters of an earthquake that occurred on January 7, 2025, in Dingri, Xizang, with the radiated energy, energy-moment ratio, slowness parameter, and apparent stress investigated. Static source parameters such as the seismic moment and moment magnitude were also determined. The main results were as follows: (1) the radiated energy of the earthquake was 9.73×1014 J, corresponding to an energy magnitude ME of 7.1, with a source rupture time of 24 s; (2) the focal mechanism was normal faulting, with the seismic moment of 4.98×1019 N·m corresponding to a moment magnitude MW of 7.1. Nodal plane I was focused at 191°/32°/−67° while plane II was at 344°/60°/−104°, and the centroid depth was 12.3 km; (3) the energy-moment ratio of the earthquake was 1.95×10–5, the slowness parameter was −4.71, and the apparent stress was 0.59 MPa. The energy-moment ratio was thus higher than the average for normal fault earthquakes on the Chinese mainland. In conclusion, the results indicated that the 2025 earthquake was a normal fault earthquake with relatively high energy release efficiency and significant potential for damage to local buildings and the infrastructure, as verified by the severe damage to ground structures and significant casualties nearby.
{"title":"Determination of radiated energy and energy-moment ratio for the 2025 Dingri, Xizang M6.8 earthquake","authors":"Yixiao Zhang, Ruifeng Liu, Zibo Wang, Zan Li","doi":"10.1016/j.eqs.2025.02.002","DOIUrl":"10.1016/j.eqs.2025.02.002","url":null,"abstract":"<div><div>Radiated seismic energy is a quantitative characteristic of an earthquake that depends not only on the initial and final stresses, but also on the rupture history, and reflects the dynamic characteristics of the source. The seismic wave energy radiated per unit of seismic moment, or energy-moment ratio, represents the balance between the stress drop, source rupture velocity, and variation in the shear wave velocity. Earthquakes with a high energy-moment ratio thus release strain energy more rapidly. The accurate and rapid determination of radiated seismic energy and the energy-moment ratio play an important role in seismic hazard assessment, quantitative earthquake research, and engineering seismology research. In this study, waveform data from the Global Seismographic Network were used to measure the dynamic source parameters of an earthquake that occurred on January 7, 2025, in Dingri, Xizang, with the radiated energy, energy-moment ratio, slowness parameter, and apparent stress investigated. Static source parameters such as the seismic moment and moment magnitude were also determined. The main results were as follows: (1) the radiated energy of the earthquake was 9.73×10<sup>14</sup> J, corresponding to an energy magnitude <em>M</em><sub>E</sub> of 7.1, with a source rupture time of 24 s; (2) the focal mechanism was normal faulting, with the seismic moment of 4.98×10<sup>19</sup> N·m corresponding to a moment magnitude <em>M</em><sub>W</sub> of 7.1. Nodal plane I was focused at 191°/32°/−67° while plane II was at 344°/60°/−104°, and the centroid depth was 12.3 km; (3) the energy-moment ratio of the earthquake was 1.95×10<sup>–5</sup>, the slowness parameter was −4.71, and the apparent stress was 0.59 MPa. The energy-moment ratio was thus higher than the average for normal fault earthquakes on the Chinese mainland. In conclusion, the results indicated that the 2025 earthquake was a normal fault earthquake with relatively high energy release efficiency and significant potential for damage to local buildings and the infrastructure, as verified by the severe damage to ground structures and significant casualties nearby.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 6","pages":"Pages 564-574"},"PeriodicalIF":4.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719033","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}
Pub Date : 2025-12-01DOI: 10.1016/j.eqs.2025.08.004
Zeyan Zhao , Han Yue , Jian Zhang , Yan Hu , Yijian Zhou , Jing Liu-Zeng , Kang Wang
The 2015 Gorkha (MW=7.8) earthquake ruptured the downdip portion of the Main Himalayan Thrust. Afterslip following this event provides valuable insights into the frictional properties on the thrust interface, yet its amplitude and distribution remain controversial. In this study, we incorporate long-term GNSS and InSAR data and correct for the viscoelastic relaxation simulated using a regional 3-D viscoelastic model. We adopt the corrected data in a novel inversion algorithm and resolve two spatially separated afterslip processes with different decay times: fast afterslip near the bottom of the coseismic rupture, possibly stopped the mainshock and triggered the MW7.3 aftershock 17 days later, and slow afterslip extending further downdip. By comparing the afterslip and aftershock patterns, we identify distinct partitioning of seismic and aseismic slip behaviors at the bottom of the seismogenic zone, which reflects local heterogeneities in frictional properties at the transition depths.
{"title":"Co-existing fast and slow afterslip processes following the 2015 Gorkha (MW7.8) earthquake resolved by full time-series inversion","authors":"Zeyan Zhao , Han Yue , Jian Zhang , Yan Hu , Yijian Zhou , Jing Liu-Zeng , Kang Wang","doi":"10.1016/j.eqs.2025.08.004","DOIUrl":"10.1016/j.eqs.2025.08.004","url":null,"abstract":"<div><div>The 2015 Gorkha (<em>M</em><sub>W</sub>=7.8) earthquake ruptured the downdip portion of the Main Himalayan Thrust. Afterslip following this event provides valuable insights into the frictional properties on the thrust interface, yet its amplitude and distribution remain controversial. In this study, we incorporate long-term GNSS and InSAR data and correct for the viscoelastic relaxation simulated using a regional 3-D viscoelastic model. We adopt the corrected data in a novel inversion algorithm and resolve two spatially separated afterslip processes with different decay times: fast afterslip near the bottom of the coseismic rupture, possibly stopped the mainshock and triggered the <em>M</em><sub>W</sub>7.3 aftershock 17 days later, and slow afterslip extending further downdip. By comparing the afterslip and aftershock patterns, we identify distinct partitioning of seismic and aseismic slip behaviors at the bottom of the seismogenic zone, which reflects local heterogeneities in frictional properties at the transition depths.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 6","pages":"Pages 485-503"},"PeriodicalIF":4.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719035","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}
Pub Date : 2025-12-01DOI: 10.1016/j.eqs.2025.08.003
Yi Wang , Baichen Wu , Yuqing Zheng , Yan Luo , Xiaohui He , Manzhong Qin
High resolution imaging of the fault zone structure is crucial to understanding the characteristics of strong earthquake activity and the deep seismogenic environment. In seismological studies, the fault zone is generally considered to be a low velocity zone with host rock on both sides. In order to determine the main parameters of fault zone, such as physical properties and interface characteristics, many efforts have been made. However, many key fault parameters still lack constraints, such as the depth extent, width and dip angle of the low velocity zone. With the advancement of the large-N array techniques in recent years, seismologists have collected high-quality data with larger apertures and denser arrays for better analysis of fault zone structures. These array data have also facilitated the development of new seismic imaging techniques. In this paper, a new waveform inversion method for fault zone parameters based on generalized teleseismic waveforms is proposed. Generalized teleseismic event is defined as the local seismic signal whose epicentral distance is greater than 7−10 times the aperture of the array. In order to efficiently simulate high frequency wavefield propagation from long distance local earthquakes, a hybrid modeling approach is proposed, which greatly reduces the computational cost for teleseismic waveform inversion. We apply the proposed new inversion method to a dense array data across an inactive fault in the Qilian Mountains, Gansu Province. As an active-source analogue of generalized teleseismic, the recorded waveforms of a 270-meter-long linear array are clearly excited by an airgun source 1.8 km away. Setting cross-correlation travel time of direct P wave as the misfit function, we perform waveform inversion for the main structural parameters of the fault zone through grid search strategy. The new method is particularly suitable for imaging fault zones with limited local seismicity.
{"title":"Waveform inversion of the fault zone structure based on generalized teleseismic wave records","authors":"Yi Wang , Baichen Wu , Yuqing Zheng , Yan Luo , Xiaohui He , Manzhong Qin","doi":"10.1016/j.eqs.2025.08.003","DOIUrl":"10.1016/j.eqs.2025.08.003","url":null,"abstract":"<div><div>High resolution imaging of the fault zone structure is crucial to understanding the characteristics of strong earthquake activity and the deep seismogenic environment. In seismological studies, the fault zone is generally considered to be a low velocity zone with host rock on both sides. In order to determine the main parameters of fault zone, such as physical properties and interface characteristics, many efforts have been made. However, many key fault parameters still lack constraints, such as the depth extent, width and dip angle of the low velocity zone. With the advancement of the large-<em>N</em> array techniques in recent years, seismologists have collected high-quality data with larger apertures and denser arrays for better analysis of fault zone structures. These array data have also facilitated the development of new seismic imaging techniques. In this paper, a new waveform inversion method for fault zone parameters based on generalized teleseismic waveforms is proposed. Generalized teleseismic event is defined as the local seismic signal whose epicentral distance is greater than 7−10 times the aperture of the array. In order to efficiently simulate high frequency wavefield propagation from long distance local earthquakes, a hybrid modeling approach is proposed, which greatly reduces the computational cost for teleseismic waveform inversion. We apply the proposed new inversion method to a dense array data across an inactive fault in the Qilian Mountains, Gansu Province. As an active-source analogue of generalized teleseismic, the recorded waveforms of a 270-meter-long linear array are clearly excited by an airgun source 1.8 km away. Setting cross-correlation travel time of direct P wave as the misfit function, we perform waveform inversion for the main structural parameters of the fault zone through grid search strategy. The new method is particularly suitable for imaging fault zones with limited local seismicity.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 6","pages":"Pages 504-530"},"PeriodicalIF":4.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719029","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}
Pub Date : 2025-12-01DOI: 10.1016/j.eqs.2025.08.006
Jiaxin Liu , Shunping Pei , Yicun Guo
The 1975 Haicheng earthquake represents the first successful prediction of a major earthquake in China and is the only earthquake forecast officially recognized by the United Nations. Understanding the crustal structure in the Haicheng region is critical for determining the seismogenic mechanisms of large earthquakes. Pg-wave tomography of the Haicheng region was used to obtain the upper crustal structure at depths of 5–10 km, in which lateral velocity variations indicate differences in tectonic activity within the seismogenic layer. A dataset comprising 62,610 Pg-wave arrival times was used to obtain high-resolution seismic velocity and anisotropy images of the upper crust in the Haicheng region. The tomography results indicate that a distinct high-velocity anomaly is located in the region that produced the Haicheng and Xiuyan earthquakes, as well as a few small earthquakes at the southern end of the Jinzhou fault. This suggests that a high-velocity asperity beneath the Haichenghe fault was able to accumulate stress due to long-term tectonic loading, eventually producing the Haicheng earthquake. The seismogenesis of Haicheng earthquake can also be used to explain other large earthquakes in the slowly deforming eastern region of China.
{"title":"High-resolution tomography of P-wave velocity structures in the Haicheng region: Implications for the seismogenesis of the 1975 MS7.3 Haicheng earthquake","authors":"Jiaxin Liu , Shunping Pei , Yicun Guo","doi":"10.1016/j.eqs.2025.08.006","DOIUrl":"10.1016/j.eqs.2025.08.006","url":null,"abstract":"<div><div>The 1975 Haicheng earthquake represents the first successful prediction of a major earthquake in China and is the only earthquake forecast officially recognized by the United Nations. Understanding the crustal structure in the Haicheng region is critical for determining the seismogenic mechanisms of large earthquakes. Pg-wave tomography of the Haicheng region was used to obtain the upper crustal structure at depths of 5–10 km, in which lateral velocity variations indicate differences in tectonic activity within the seismogenic layer. A dataset comprising 62,610 Pg-wave arrival times was used to obtain high-resolution seismic velocity and anisotropy images of the upper crust in the Haicheng region. The tomography results indicate that a distinct high-velocity anomaly is located in the region that produced the Haicheng and Xiuyan earthquakes, as well as a few small earthquakes at the southern end of the Jinzhou fault. This suggests that a high-velocity asperity beneath the Haichenghe fault was able to accumulate stress due to long-term tectonic loading, eventually producing the Haicheng earthquake. The seismogenesis of Haicheng earthquake can also be used to explain other large earthquakes in the slowly deforming eastern region of China.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 6","pages":"Pages 590-600"},"PeriodicalIF":4.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145719034","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}
Pub Date : 2025-09-02DOI: 10.1016/j.eqs.2025.06.006
Shuguang Wang , Shuoxian Ning , Zhixiang Yao , Jiaqi Li , Wanbo Xiao , Tianfan Yan , Feng Xu
The InSight mission has obtained seismic data from Mars, offering new insights into the planet’s internal structure and seismic activity. However, the raw data released to the public contain various sources of noise, such as ticks and glitches, which hamper further seismological studies. This paper presents step-by-step processing of InSight’s Very Broad Band seismic data, focusing on the suppression and removal of non-seismic noise. The processing stages include tick noise removal, glitch signal suppression, multicomponent synchronization, instrument response correction, and rotation of orthogonal components. The processed datasets and associated codes are openly accessible and will support ongoing efforts to explore the geophysical properties of Mars and contribute to the broader field of planetary seismology.
{"title":"Basic processing of the InSight seismic data from Mars for further seismological research","authors":"Shuguang Wang , Shuoxian Ning , Zhixiang Yao , Jiaqi Li , Wanbo Xiao , Tianfan Yan , Feng Xu","doi":"10.1016/j.eqs.2025.06.006","DOIUrl":"10.1016/j.eqs.2025.06.006","url":null,"abstract":"<div><div>The InSight mission has obtained seismic data from Mars, offering new insights into the planet’s internal structure and seismic activity. However, the raw data released to the public contain various sources of noise, such as ticks and glitches, which hamper further seismological studies. This paper presents step-by-step processing of InSight’s Very Broad Band seismic data, focusing on the suppression and removal of non-seismic noise. The processing stages include tick noise removal, glitch signal suppression, multicomponent synchronization, instrument response correction, and rotation of orthogonal components. The processed datasets and associated codes are openly accessible and will support ongoing efforts to explore the geophysical properties of Mars and contribute to the broader field of planetary seismology.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 5","pages":"Pages 450-460"},"PeriodicalIF":4.1,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933774","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}
Pub Date : 2025-09-02DOI: 10.1016/j.eqs.2025.06.002
Shanshan Jia , Laiyu Lu , Yutao Shi , Pingping Wu , Lijun Chang
The Sichuan-Yunnan Block is located on the southeastern margin of the Qinghai-Xizang Plateau and has frequent seismic activity on the western border, posing a potential threat to human society and economic development. Therefore, it is important to understand its geological evolution, assess earthquake risks, and formulate scientific and reasonable disaster prevention and mitigation strategies. Using 23 months of continuous ambient noise records from 81 seismic stations, we obtained 1248 phase-velocity dispersion curves of the fundamental Rayleigh wave at 5–50 s. The three-dimensional (3D) S-wave velocity structure in the northwestern Sichuan-Yunnan Block was obtained by pure-path and depth inversion. The results show that three low-velocity anomalous bands were distributed nearly north-to-south (N-S) at depths of 10–35 km. The overall shape of the low-velocity channel gradually shifted from southeast to southwest because of the influence of the Panzhihua high-velocity blocks. The low-velocity strip consists of three branches, with the first branch extending southwest from the northern part of the Lancangjiang Fault. The second branch is distributed in the N-S direction and is blocked by two high-velocity bodies near the Longpan-Qiaohou and Honghe faults. The third branch crosses the research area from N-S and gradually extends from southeast to southwest and from shallow to deep. The three low-velocity anomaly distribution areas are likely the most severely deformed areas of the collision between the Qinghai-Xizang Plateau and Yangtze Block. The results provide a more detailed understanding of the deep structure of the western boundary of the Sichuan-Yunnan Block crustal low-velocity anomalies and reliable geophysical evidence for the morphology and continuity of crustal flows.
{"title":"High-resolution 3D S-wave velocity structure in northwestern Sichuan-Yunnan Block derived from ambient noise tomography","authors":"Shanshan Jia , Laiyu Lu , Yutao Shi , Pingping Wu , Lijun Chang","doi":"10.1016/j.eqs.2025.06.002","DOIUrl":"10.1016/j.eqs.2025.06.002","url":null,"abstract":"<div><div>The Sichuan-Yunnan Block is located on the southeastern margin of the Qinghai-Xizang Plateau and has frequent seismic activity on the western border, posing a potential threat to human society and economic development. Therefore, it is important to understand its geological evolution, assess earthquake risks, and formulate scientific and reasonable disaster prevention and mitigation strategies. Using 23 months of continuous ambient noise records from 81 seismic stations, we obtained 1248 phase-velocity dispersion curves of the fundamental Rayleigh wave at 5–50 s. The three-dimensional (3D) S-wave velocity structure in the northwestern Sichuan-Yunnan Block was obtained by pure-path and depth inversion. The results show that three low-velocity anomalous bands were distributed nearly north-to-south (N-S) at depths of 10–35 km. The overall shape of the low-velocity channel gradually shifted from southeast to southwest because of the influence of the Panzhihua high-velocity blocks. The low-velocity strip consists of three branches, with the first branch extending southwest from the northern part of the Lancangjiang Fault. The second branch is distributed in the N-S direction and is blocked by two high-velocity bodies near the Longpan-Qiaohou and Honghe faults. The third branch crosses the research area from N-S and gradually extends from southeast to southwest and from shallow to deep. The three low-velocity anomaly distribution areas are likely the most severely deformed areas of the collision between the Qinghai-Xizang Plateau and Yangtze Block. The results provide a more detailed understanding of the deep structure of the western boundary of the Sichuan-Yunnan Block crustal low-velocity anomalies and reliable geophysical evidence for the morphology and continuity of crustal flows.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 5","pages":"Pages 408-426"},"PeriodicalIF":4.1,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933776","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}
Pub Date : 2025-09-02DOI: 10.1016/j.eqs.2025.06.004
Lei Li , Jiacheng Zhang , Yuyang Tan , Ling Peng , Junlun Li , Jincheng Xu , Jianxin Liu
Seismic source locations can characterize the spatial and temporal distributions of seismic sources, and can provide important basic data for earthquake disaster monitoring, fault activity characterization, and fracture growth interpretation. Waveform stacking-based location methods invert the source locations by focusing the source energy with multichannel waveforms, and these methods exhibit a high level of automation and noise-resistance. Taking the cross-correlation stacking (CCS) method as an example, this work attempts to study the influential factors of waveform stacking-based methods, and introduces a comprehensive performance evaluation scheme based on multiple parameters and indicators. The waveform data are from field monitoring of induced microseismicity in the Changning region (southern Sichuan Basin of China). Synthetic and field data tests reveal the impacts of three categories of factors on waveform stacking-based location: velocity model, monitoring array, and waveform complexity. The location performance is evaluated and further improved in terms of the source imaging resolution and location error. Denser array monitoring contributes to better constraining source depth and location reliability, but the combined impact of multiple factors, such as velocity model uncertainty and multiple seismic phases, increases the complexity of locating field microseismic events. Finally, the aspects of location uncertainty, phase detection, and artificial intelligence-based location are discussed.
{"title":"Performance evaluation of the waveform stacking-based microseismic location method in the southern Sichuan Basin of China","authors":"Lei Li , Jiacheng Zhang , Yuyang Tan , Ling Peng , Junlun Li , Jincheng Xu , Jianxin Liu","doi":"10.1016/j.eqs.2025.06.004","DOIUrl":"10.1016/j.eqs.2025.06.004","url":null,"abstract":"<div><div>Seismic source locations can characterize the spatial and temporal distributions of seismic sources, and can provide important basic data for earthquake disaster monitoring, fault activity characterization, and fracture growth interpretation. Waveform stacking-based location methods invert the source locations by focusing the source energy with multichannel waveforms, and these methods exhibit a high level of automation and noise-resistance. Taking the cross-correlation stacking (CCS) method as an example, this work attempts to study the influential factors of waveform stacking-based methods, and introduces a comprehensive performance evaluation scheme based on multiple parameters and indicators. The waveform data are from field monitoring of induced microseismicity in the Changning region (southern Sichuan Basin of China). Synthetic and field data tests reveal the impacts of three categories of factors on waveform stacking-based location: velocity model, monitoring array, and waveform complexity. The location performance is evaluated and further improved in terms of the source imaging resolution and location error. Denser array monitoring contributes to better constraining source depth and location reliability, but the combined impact of multiple factors, such as velocity model uncertainty and multiple seismic phases, increases the complexity of locating field microseismic events. Finally, the aspects of location uncertainty, phase detection, and artificial intelligence-based location are discussed.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 5","pages":"Pages 427-440"},"PeriodicalIF":4.1,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933777","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}
Pub Date : 2025-09-02DOI: 10.1016/j.eqs.2025.06.003
Xianwei Zeng , Chunquan Yu
We present CrazyBeachball, a MATLAB-based graphical user interface (GUI) software package designed for focal mechanism inversion using P-wave first-motion polarity and S/P amplitude ratio data. CrazyBeachball integrates seismic waveform visualization, first-motion polarity picking, and focal mechanism inversion into a single, interactive platform. Unlike conventional methods that involve separate, independent steps, CrazyBeachball streamlines the process and eliminates the need for external data conversion. Its user-friendly interface allows for efficient focal mechanism determination, while its human-machine interaction facilitates enhanced quality control. We demonstrate its effectiveness by determining focal mechanisms for 21 aftershocks from the 2021 MS6.4 Yangbi earthquake sequence, with results aligning with the regional stress field and fault zone geometry. This open-source software package also allows for user customization, enabling adaptation for specific research needs.
{"title":"CrazyBeachball: A MATLAB GUI-based software package for focal mechanism inversion","authors":"Xianwei Zeng , Chunquan Yu","doi":"10.1016/j.eqs.2025.06.003","DOIUrl":"10.1016/j.eqs.2025.06.003","url":null,"abstract":"<div><div>We present CrazyBeachball, a MATLAB-based graphical user interface (GUI) software package designed for focal mechanism inversion using P-wave first-motion polarity and S/P amplitude ratio data. CrazyBeachball integrates seismic waveform visualization, first-motion polarity picking, and focal mechanism inversion into a single, interactive platform. Unlike conventional methods that involve separate, independent steps, CrazyBeachball streamlines the process and eliminates the need for external data conversion. Its user-friendly interface allows for efficient focal mechanism determination, while its human-machine interaction facilitates enhanced quality control. We demonstrate its effectiveness by determining focal mechanisms for 21 aftershocks from the 2021 <em>M</em><sub>S</sub>6.4 Yangbi earthquake sequence, with results aligning with the regional stress field and fault zone geometry. This open-source software package also allows for user customization, enabling adaptation for specific research needs.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 5","pages":"Pages 441-449"},"PeriodicalIF":4.1,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933778","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}
Pub Date : 2025-09-02DOI: 10.1016/j.eqs.2025.06.001
Lanbo Liu
Dilatancy is referred to the phenomenon of volume increase that occurs when a material is deformed. Dilatancy theory originated in geomechanics for the study of the behavior of granular materials. Later it is expanded to the case of more brittle materials like rocks when it is subjected to the load of varying effective stress and starts to crack and deform, then named the dilatancy-diffusion hypothesis. This hypothesis was developed to explain the changes in rock volume and pore pressure that occur prior to and during fault slip, which can influence earthquake dynamics. Dilatancy-fluid diffusion is a significant concept in understanding the seismogenic process and has served as the major theoretical pillar for earthquake prediction by its classic definition. This paper starts with the recount of fundamental laboratory experiments on granular materials and rocks, then conducts review and examination of the history for using the dilatancy-diffusion hypothesis to interpret the ‘prediction’ of the 1975 Haicheng Earthquake and other events. The Haicheng Earthquake is the first significant event to be interpreted with the dilatancy-diffusion hypothesis in the world. As one pivotal figure in the development of the dilatancy-diffusion hypothesis for earthquake prediction Professor Amos Nur of Stanford University worked tirelessly to attract societal attention to this important scientific and humanistic issue. As a deterministic physical model the dilatancy-diffusion hypothesis intrinsically bears the deficit to interpret the stochastic seismogenic process. With the emergence of deep learning and its successful applications to many science and technology fields, we may see a possibility to overcome the shortcoming of the current state of the theory with the addition of empirical statistics to push the operational earthquake forecasting approach with the addition of the physically-informed neural networks which adopt the dilatancy-diffusion hypothesis as one of its embedded physical relations, to uplift the seismic risk reduction to a new level for saving lives and reducing the losses.
{"title":"The dilatancy-diffusion hypothesis, earthquake prediction, and operational earthquake forecasting: In memory of Professor Amos Nur on the 50th Anniversary of the 1975 Haicheng Earthquake","authors":"Lanbo Liu","doi":"10.1016/j.eqs.2025.06.001","DOIUrl":"10.1016/j.eqs.2025.06.001","url":null,"abstract":"<div><div>Dilatancy is referred to the phenomenon of volume increase that occurs when a material is deformed. Dilatancy theory originated in geomechanics for the study of the behavior of granular materials. Later it is expanded to the case of more brittle materials like rocks when it is subjected to the load of varying effective stress and starts to crack and deform, then named the dilatancy-diffusion hypothesis. This hypothesis was developed to explain the changes in rock volume and pore pressure that occur prior to and during fault slip, which can influence earthquake dynamics. Dilatancy-fluid diffusion is a significant concept in understanding the seismogenic process and has served as the major theoretical pillar for earthquake prediction by its classic definition. This paper starts with the recount of fundamental laboratory experiments on granular materials and rocks, then conducts review and examination of the history for using the dilatancy-diffusion hypothesis to interpret the ‘prediction’ of the 1975 Haicheng Earthquake and other events. The Haicheng Earthquake is the first significant event to be interpreted with the dilatancy-diffusion hypothesis in the world. As one pivotal figure in the development of the dilatancy-diffusion hypothesis for earthquake prediction Professor Amos Nur of Stanford University worked tirelessly to attract societal attention to this important scientific and humanistic issue. As a deterministic physical model the dilatancy-diffusion hypothesis intrinsically bears the deficit to interpret the stochastic seismogenic process. With the emergence of deep learning and its successful applications to many science and technology fields, we may see a possibility to overcome the shortcoming of the current state of the theory with the addition of empirical statistics to push the operational earthquake forecasting approach with the addition of the physically-informed neural networks which adopt the dilatancy-diffusion hypothesis as one of its embedded physical relations, to uplift the seismic risk reduction to a new level for saving lives and reducing the losses.</div></div>","PeriodicalId":46333,"journal":{"name":"Earthquake Science","volume":"38 5","pages":"Pages 465-484"},"PeriodicalIF":4.1,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933773","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}
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