ANALYSIS OF BUILDING DAMAGE AND CASUALTIES OF THE 2025 DINGRI MS6.8 EARTHQUAKE IN XIZANG BASED ON FIELD INVESTIGATION

doi:10.3969/j.issn.0253-4967.2025.01.005

Abstract

Abstract:

On January 7, 2025, at 9:05 AM, a magnitude 6.8 earthquake struck Dingri County, Shigatse City, located in the southern part of the Xizang Autonomous Region(28.50°N, 87.45°E), with a focal depth of 10 kilometers. By 7:00 PM on January 9, the earthquake had resulted in 126 fatalities and 188 injuries. A total of 27, 248 buildings were damaged, including 3, 612 collapsed structures. Timely understanding and analysis of the earthquake's damage characteristics and the causes of casualties can provide valuable references for subsequent disaster loss assessments and recovery planning.

Based on field investigations, this study provides a comprehensive overview of the earthquake damage, covering four main aspects: seismic characteristics and affected areas, seismogenic fault and aftershock distribution, building damage and influencing factors, and the distribution and causes of casualties. The study also analyzes in detail the reasons for the severe casualties in this earthquake.

The epicenter of the Dingri earthquake is located within the Lhasa block of the Tibetan Plateau. The earthquake was triggered by the Dengmecuo fault, a normal fault characterized by crustal extension due to fault slip. The maximum intensity of this earthquake reached IX degree, and the major axis of the isoseismal line runs nearly north-south, with a length of 191 kilometers and a short axis of 152 kilometers. The area affected by intensity VI or higher is approximately 23986 square kilometers, covering six counties and 45 towns(or streets)in Shigatse City, Xizang Autonomous Region. The earthquake caused a surface rupture of approximately 26 kilometers, with a maximum vertical displacement of about 3 meters.

Field investigations revealed that the building structures in Dingri County mainly consist of frame, masonry, and traditional civil structures. Among these, traditional civil structures sustained the most severe damage. In extremely and severely affected areas, the majority of civil-structure buildings were either destroyed or severely damaged, with complete or partial collapses occurring. The main factors contributing to the severe damage to civil-structure buildings include the lack of seismic resistance measures, poor construction techniques, and inadequate shear resistance and bond strength of construction materials.

The majority of casualties were concentrated in Changsuo, Cuoguo, and Quluo towns, near the epicenter. Changsuo town suffered the most severe damage, with casualties accounting for 74.60% of the total fatalities. The high casualty rate can be attributed to the strong destructive power of the earthquake, the proximity of villages to the fault lines, low seismic performance of buildings, high population density, and adverse environmental conditions such as low temperatures and oxygen deficiency.

Based on the analysis of the causes of casualties and field investigations, this study proposes targeted countermeasures and suggestions to mitigate earthquake disaster risks and minimize casualties in Xizang. These measures include enhancing active fault detection, improving earthquake early warning capabilities, reducing seismic damage risks to traditional residential buildings, strengthening emergency response measures, mitigating the risk of secondary earthquake disasters, and increasing public awareness of earthquake risks. These recommendations aim to enhance the region's earthquake prevention and mitigation capabilities and provide guidance for post-disaster recovery and reconstruction.

Key words: Dingri M_S6.8 earthquake, earthquake damage analysis, casualties, Xizang

摘要：

2025年1月7日9时5分, 西藏南部日喀则市定日县发生6.8级地震。此次地震已造成126人遇难, 188人受伤, 大量房屋倒塌。根据现场调查, 土木结构房屋是此次地震中受影响最大, 破坏最严重的房屋类型。地震遇难者集中分布于震中附近的定日县长所乡、措果乡和曲洛乡, 其中长所乡受灾最为严重, 遇难人数占总遇难人数的74.60%。地震破坏力强、村落临近发震断层、房屋建筑抗震性能低、高人员在室率及低温缺氧等是造成此次地震人员伤亡高的主要原因。基于人员伤亡原因分析和现场调查, 文中从加强活动断层探测、提升地震预警能力、降低传统民居震害风险、夯实应急保障措施、防范地震次生灾害风险及加强风险意识宣传教育等6个方面, 提出了针对性地降低西藏地区震害风险、减少人员伤亡的对策建议, 以期为当地防震减灾能力提升和灾后恢复重建提供参考。

关键词: 定日M_S6.8地震, 震害分析, 人员伤亡, 西藏

WEI Ben-yong, ZHANG Yu-man, SHI Feng, QIAO Jun-xiang, WANG Xin, ZHANG Da. ANALYSIS OF BUILDING DAMAGE AND CASUALTIES OF THE 2025 DINGRI M_S6.8 EARTHQUAKE IN XIZANG BASED ON FIELD INVESTIGATION[J]. SEISMOLOGY AND GEOLOGY, 2025, 47(1): 64-79.

魏本勇, 张钰曼, 石峰, 乔俊香, 王鑫, 张达. 基于现场调查的2025西藏定日M_S6.8地震房屋震害与人员伤亡分析[J]. 地震地质, 2025, 47(1): 64-79.

Figures/Tables 9

Fig. 1 Seismic intensity map of the MS6.8 earthquake in Dingri, Xizang.

Fig. 2 Regional seismic structure and aftershock distribution of the Dingri MS6.8 earthquake.

Fig. 3 Seismic source mechanism solution of the Dingri MS6.8 earthquake.

Fig. 4 Photo showing surface fractures produced by the Dingri MS6.8 earthquake(SHI Feng et al., 2025).

Fig. 5 Examples of seismic damage to civil structural buildings.

Fig. 6 Examples of seismic damage to brick concrete structures in Quluo(a) and Cuoguo town(b).

Fig. 7 Examples of seismic damage to the framework structure in Quluo town.

Fig. 8 Location distribution of victims in the Dingri MS6.8 earthquake.

Fig. 9 Plot of victim number with age in the Dingri MS6.8 earthquake.

References 16

[1]	崔玥, 杨娜. 2023. 藏式山地古建筑结构特征及抗震性能[J]. 建筑结构学报, 44(S2): 20—31.
	CUI Yue, YANG Na. 2023. Structural characteristics and seismic performance of ancient Zang-style architecture on sloped lands[J]. Journal of Building Structures, 44(S2): 20—31 (in Chinese).
[2]	黄婷, 吴中海, 韩帅, 等. 2024. 西藏日喀则地区的活断层基本特征及地震灾害潜在风险评估[J]. 地震科学进展, 54(10): 696—711.
	HUANG Ting, WU Zhong-hai, HAN Shuai, et al. 2024. The basic characteristics of active faults in the region of Xigaze, Xizang and the assessment of potential earthquake disaster risks[J]. Progress in Earthquake Sciences, 54(10): 696—711 (in Chinese).
[3]	李碧雄, 王甜恬, 赵开鹏, 等. 2021. 传统藏式民居的典型震害及易损性研究[J]. 建筑结构学报, 42(S1): 165—173.
	LI Bi-xiong, WANG Tian-tian, ZHAO Kai-peng, et al. 2021. Typical earthquake damage of traditional Tibetan dwellings and its vulnerability[J]. Journal of Building Structures, 42(S1): 165—173 (in Chinese).
[4]	李志强, 侯建盛, 李洋, 等. 2013a. 2013年4月20日四川芦山 M_S7.0 地震灾害特点分析[J]. 地震地质, 35(2): 398—410. doi: 10.3969/j.issn.0253-4967.2013.02.018.
	LI Zhi-qiang, HOU Jian-sheng, LI Yang, et al. 2013a. Analysis on the characteristics of the M_S7.0 Lushan earthquake hazard in Sichuan Province on April 20th, 2013[J]. Seismology and Geology, 35(2): 398—410 (in Chinese).
[5]	李志强, 姜立新, 李亦纲, 等. 2013b. 2013年7月22日甘肃岷县漳县 M_S6.6 地震灾害特点分析[J]. 地震地质, 35(3): 593—603. doi: 10.3969/j.issn.0253-4967.2013.03.013.
	LI Zhi-qiang, JIANG Li-xin, LI Yi-gang, et al. 2013b. Analysis on the characteristics of the M_S6.6 Minxian-Zhangxian earthquake hazard in Gansu Province, China on July 22, 2013[J]. Seismology and Geology, 35(3): 593—603 (in Chinese).
[6]	李志强, 袁一凡, 李晓丽, 等. 2008. 汶川 M_S8.0 特大地震破坏特征初步研究[J]. 地震地质, 30(4): 855—876. doi: 10.3969/j.issn.0253-4967.2008.04.004.
	LI Zhi-qiang, YUAN Yi-fan, LI Xiao-li, et al. 2008. Preliminary research on the characteristics of the M_S8.0 Wenchuan earthquake hazard[J]. Seismology and Geology, 30(4): 855—876 (in Chinese).
[7]	李宗超, 吴健, 李昌珑. 2018. 西藏米林 M_S6.9 地震震害分析[J]. 国际地震动态, (12): 2—9.
	LI Zong-chao, WU Jian, LI Chang-long. 2018. Seismic hazard analysis of building structures for Milin M_S6.9 earthquake, Tibet[J]. Recent Developments in World Seismology, (12): 2—9 (in Chinese).
[8]	石峰, 梁明剑, 罗全星, 等. 2025. 2025年1月7日西藏定日6.8级地震发震构造与同震地表破裂特征[J]. 地震地质, 47(1): 1—15. doi: 10.3969/j.issn.0253-4967.2025.01.001.
	SHI Feng, LIANG Ming-jian, LUO Quan-xing, et al. 2025. Seismogenic fault and coseismic surface deformation of the Dingri M_S6.8 earthquake in Tibet, China[J]. Seismology and Geology, 47(1): 1—15 (in Chinese).
[9]	宋立军, 梁志远, 舒海疆, 等. 2022. 低温环境下城市“大震巨灾”应急处置[J]. 城市与减灾, (2): 18—22.
	SONG Li-jun, LIANG Zhi-yuan, SHU Hai-jiang, et al. 2022. Emergency disposal for urban catastrophe caused by great earthquakes at low temperature[J]. City and Disaster Reduction, (2): 18—22 (in Chinese).
[10]	王郁, 刘爱文, 李祥秀, 等. 2021. 基于震害资料的西藏地区典型民居易损性分析[J]. 震灾防御技术, 16(2): 245—252.
	WANG Yu, LIU Ai-wen, LI Xiang-xiu, et al. 2021. Vulnerability analysis of typical dwellings in Tibet based on earthquake damage data[J]. Technology for Earthquake Disaster Prevention, 16(2): 245—252 (in Chinese).
[11]	魏本勇. 2018. 中国地震监测预警预报体系现状概述[J]. 中国减灾, (15): 20—21.
	WEI Ben-yong. 2018. Overview of the current status of China's earthquake monitoring, early warning, and forecasting system[J]. Journal of Disaster Reduction in China, (15): 20—21 (in Chinese).
[12]	许月怡, 张勇. 2023. 从震源破裂过程角度分析中国大陆强震面波震级高于矩震级的原因[J]. 北京大学学报(自然科学版), 59(3): 407—414.
	XU Yue-yi, ZHANG Yong. 2023. Analysis of the Reasons why surface wave magnitude is higher than moment magnitude in the mainland of China from the perspective of source rupture parameters[J]. Acta Scientiarum Naturalium Universitatis Pekinensis, 59(3): 407—414 (in Chinese).
[13]	Dal Z L, Ampuero J P. 2023. Earthquake Doublet in Turkey and Syria[J]. Communications Earth & Environment, 4:71.
[14]	Wei B Y, Nie G Z, Su G W, et al. 2017. Risk assessment of people trapped in earthquake based on km grid: A case study of the 2014 Ludian earthquake, China[J]. Geomatics, Natural Hazards and Risk, 8(2): 1289—1305. doi: 10.1080/19475705.2017.1318795.
[15]	Wei B Y, Nie G Z, Su G W, et al. 2022. Risk assessment of people trapped in earthquake disasters based on a single building: A case study in Xichang City, Sichuan Province, China[J]. Geomatics, Natural Hazards and Risk, 13(1): 167—192. doi: 10.1080/19475705.2021.2017358.
[16]	Wei B Y, Su G W, Liu F G, et al. 2021. Public cognition and response to earthquake disaster: From the 2008 M_W7.9 Wenchuan to the 2013 M_W6.6 Lushan earthquakes in Sichuan Province, China[J]. Natural Hazards, 106(3): 2751—2774. doi: 10.1007/s11069-021-04564-5.