2025年西藏定日6.8级地震序列特征及发震构造
中国地震台网中心, 北京 100045
中国地震局地震研究所, 武汉 430071
四川省地震局, 成都 610041
甘肃省地震局, 兰州 730000
甘肃兰州地球物理国家野外科学观测研究站, 兰州 730000
中国地震局地球物理研究所, 北京 100081
西藏自治区地震局, 拉萨 850000
香港中文大学地球与环境科学系, 香港 999077
香港中文大学深圳研究院, 深圳 518057
国家自然科学基金(42430303)，中国地震局星火计划项目(XH23030B)，香港研究资助局(14306122, 14308523)联合资助.
中图分类号:P315
China Earthquake Networks Center, Beijing 100045, China
Institute of Seismology, China Earthquake Administration, Wuhan 430071, China
Sichuan Earthquake Agency, Chengdu 610041, China
Gansu Earthquake Agency, Lanzhou 730000, China
Gansu Lanzhou Geophysics National Observation and Research Station, Lanzhou 730000, China
Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
Earthquake Agency of Xizang Autonomous Region, Lhasa 850000, China
Department of Earth and Environmental Sciences, The Chinese University of Hong Kong, Hong Kong 999077, China
Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China
In this study we use continuous waveform data and seismic phase reports from the China Earthquake Networks Center (CENC) to detect the foreshock sequence of the January 7, 2025, M6.8 Xizang Tingri earthquake using deep learning method. We employ the double-difference relocation method to relocate the entire sequence. We calculate focal mechanism solutions using polarity data (M3~3.9), modelling of regional seismic waveforms (M≥4) and W phases (mainshock). Moreover, we analyze the relationship and distribution characteristics between MS and MW for earthquakes in Chinese mainland since 2013. The results show that the Tingri sequence is a typical foreshock-mainshock-aftershock sequence and the seismogenic structure is the Dengmocuo Fault within the Xainza–Dinggyê Rift. The focal mechanism of the mainshock exhibits normal faulting. The aftershock sequence extends in a north-south direction, with an aftershock zone approximately 120 km long and 60 km wide. Foreshocks and aftershocks are predominantly distributed to the north of the mainshock epicenter, within a depth range of 3 to 20 km. At certain segments of the rupture zone, e.g. cross-sections of CC′ and FF′, the distribution of earthquakes outlines a fault plane that dips slightly to the west, which is consistent with the dip direction of the Dengmocuo Fault. However, other cross-section profiles do not show clear dip directions. The foreshock sequence begins ten days before the mainshock and shows a migration pattern towards the mainshock epicenter, with a speed accelerating to ~3.9 km·h-1 one hour before the mainshock. It is hypothesized that the foreshock sequence may have occurred on a blind minor conjugate fault, triggering the mainshock and numerous aftershocks. We also analyze the relationship between MS and MW for 260 earthquakes in Chinese mainland since 2013, which exhibits clear characteristics of magnitude dependent and regional distribution. The characteristics of the 2025 Tingri sequence provide scientific insights into the earthquake preparation process and mechanism, as well as understanding the deformation mechanism and seismic hazard of the Qinghai-Xizang Plateau.
图 1研究区构造背景及台站分布
研究区构造背景及台站分布
Figure 1.Tectonic setting and the station distribution of the study area
Tectonic setting and the station distribution of the study area
Figure 2.Waveform, phases and station distribution of the ML1.8 foreshock at 14:48 on December 1, 2024
Waveform, phases and station distribution of the ML1.8 foreshock at 14:48 on December 1, 2024
图 5地震序列重定位及震源机制解
地震序列重定位及震源机制解
Figure 5.Relocation and focal mechanisms of the earthquake sequence
Relocation and focal mechanisms of the earthquake sequence
图 3西藏定日M6.8地震序列M-T图
西藏定日M6.8地震序列M-T图
Figure 3.M-T diagram of the Xizang Tingri 6.8 earthquake sequence
M-T diagram of the Xizang Tingri 6.8 earthquake sequence
图 4西藏定日M6.8地震W-phase震相波形拟合图
西藏定日M6.8地震W-phase震相波形拟合图
Figure 4.W-phase waveform fitting diagram for the Xizang Tingri M6.8 earthquake
W-phase waveform fitting diagram for the Xizang Tingri M6.8 earthquake
图 6前震序列时空演化
前震序列时空演化
Figure 6.Spatial-temporal evolution of the foreshock sequence
Spatial-temporal evolution of the foreshock sequence
图 7MS与MW差值分布图
MS与MW差值分布图
Figure 7.The distribution of the difference between MS and MW
The distribution of the difference between MS and MW
图 8MS与MW的线性关系
MS与MW的线性关系
Figure 8.Linear relationship between MS and MW
Linear relationship between MS and MW
表 1双差定位所使用的速度模型
双差定位所使用的速度模型
Table 1.The velocity model used for double-difference earthquake location
The velocity model used for double-difference earthquake location
China Earthquake Administration. 2017. DB/T 66-2016 Specification for earthquake cataloguing (in Chinese). Beijing: Seismological Press.
Duputel Z, Rivera L, Kanamori H, et al. 2012. W phase source inversion for moderate to large earthquakes (1990-2010). Geophysical Journal International, 189(2): 1125-1147.
Department of Earthquake Disaster Prevention, State Seismological Bureau. 1995. Catalogue of Historical Strong Earthquakes in China (23rd Century B. C. to 1911) (in Chinese). Beijing: Seismological Press, 514.
Department of Earthquake Disaster Prevention, China Seismological Bureau. 1999. The Catalogue of Modern Earthquakes (in Chinese). Beijing: Chinese Science and Technology Press, 1-637.
General Administration of Quality Supervision, Inspection and Quarantine of the People′s Republic of China, Standardization Administration of the People′s Republic of China. 2017. GB 17740-2017 General ruler for earthquake magnitude (in Chinese). Beijing: Standards Press of China.
Laske G, Masters G, Ma Z T, et al. 2013. Update on CRUST1.0-A1-degree Global Model of Earth′s Crust. //Geophysical Research Abstracts. EGU, 15: EGU2013-2658.
Quenouille M H. 1949. Approximate tests of correlation in time-series. Journal of the Royal Statistical Society: Series B (Methodological), 11(1): 68-84.
Quenouille M H. 1956. Notes on bias in estimation. Biometrika, 43(3-4): 353-360.
Shi F, Liang M J, Luo Q X, et al. 2025. Seismogenic fault and coseismic surface deformation of the Dingri MS6.8 Earthquake in Xizang, China. Seismology and Geology (in Chinese), 47(1): 1-15.
Tian T T, Wu Z H. 2023. Recent prehistoric major earthquake event of Dingmucuo Normal fault in the southern segment of Shenzha-Dingjie Rift and its seismic geological significance. Geological Review (in Chinese), 69(S1): 53-55.
Tukey J W. 1958. Bias and confidence in not quite large samples. The Annals of Mathematical Statistics, 29(2): 614-623.
Xie Z N, Wang S, Chen X Z, et al. 2025. The simulated instrumental seismic intensity field of the MS6.8 Dingri, Xizang earthquake on January 7, 2025. Earthquake Engineering and Engineering Dynamics (in Chinese), 45(1): 12-17.
Yong Y Y. 2012. The NS-trending structures in the southwestern part of the Qinghai-Xizang Plateau: New insights. Sedimentary Geology and Tethyan Geology (in Chinese), 32(3): 21-30.
Yu Z Y, Wang W T. 2022. FastLink: A machine learning and GPU-based fast phase association method and its application to Yangbi MS6.4 aftershock sequences. Geophysical Journal International, 230(1): 673-683.
Zhang J J, Guo L, Ding L. 2002. Structural characteristics of middle and southern Xainza-Dinggye normal fault system and its relationship to Southern Tibetan detachment system. Chinese Science Bulletin, 47(13): 1063-1069.
Zhang P Z, Deng Q D, Zhang G M, et al. 2003. Active tectonic blocks and strong earthquakes in the continent of China. Science in China Series D: Earth Sciences, 46(S2): 13-24.
Zhang Y Y, Miao C L, Chen J L, et al. 2024. Design and construction of the earthquake waveform comprehensive analysis system for National Seismic Intensity Rapid Reporting and Early Warning Project. Earthquake Research in China (in Chinese), 40(1): 40-53.
雍永源. 2012. 青藏高原西南部南北向构造研究的新见解. 沉积与特提斯地质, 32(3): 21-30.
张进江, 郭磊, 丁林. 2002. 申扎—定结正断层体系中、南段构造特征及其与藏南拆离系的关系. 科学通报, 47(10): 738-743.
张培震, 邓起东, 张国民等. 2003. 中国大陆的强震活动与活动地块. 中国科学(D辑), 33(S1): 12-20.
张莹莹, 苗春兰, 陈经纶等. 2024. 国家预警工程综合地震波形分析系统设计与实现. 中国地震, 40(1): 40-53.
中国地震局. 2017. DB/T 66-2016 地震编目规范. 北京: 地震出版社.
中国地震局震害防御司. 1999. 中国近代地震目录: 公元1912年 ~ 1990年, MS≥4.7. 北京: 中国科学技术出版社.
中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会. 2017. GB 17740-2017 地震震级的规定. 北京: 中国标准出版社.
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Tectonic setting and the station distribution of the study area
Waveform, phases and station distribution of the ML1.8 foreshock at 14:48 on December 1, 2024
Relocation and focal mechanisms of the earthquake sequence
M-T diagram of the Xizang Tingri 6.8 earthquake sequence
W-phase waveform fitting diagram for the Xizang Tingri M6.8 earthquake
Spatial-temporal evolution of the foreshock sequence
The distribution of the difference between MS and MW
Linear relationship between MS and MW