Abstract:

Earthquake disaster loss pre-assessment refers to the evaluation of potential disaster losses under scenario earthquake in key seismic hazard areas and the assessment of existing earthquake emergency preparedness capabilities. This work is typically conducted annually. In this study, we compare the actual earthquake damage, the relief supplies and rescue forces which invested in disaster relief of the Wushi M7.1 earthquake in 2024 Xijnjiang during the emergency rescue period, with the results of the annual earthquake disaster loss pre-assessment, It can be considered that the pre-assessment results of the disaster area size, casualties, the number of evacuated and relocated persons, and disaster relief needs are generally good.

Due to the potential for destructive earthquakes to cause significant casualties, casualty estimation is prioritized in annual pre-assessment work. So we conduct a retrospective evaluation of the annual pre-assessment of casualties for seven destructive earthquake which cause casualties since 2015 in Xinjiang. The pre-assessment results of three earthquakes with a magnitude of 6 are basically the same as the actual number of casualties; the other four earthquakes(including two magnitude 5 and two magnitude 6 earthquakes)did not occur within the assessment area and its 50-kilometer buffer zone, resulting in no valid evaluation outcomes.

The primary cause of earthquake casualties in Xinjiang in recent years(from 2015)is the damage of old buildings or ancillary facilities and the coseismic rupture of earthquakes. The sequence type of the earthquake and the occurrence time of the earthquake are objective factors for casualties. Foreshock may reduce casualties caused by the main shock under typical conditions. Earthquakes occurring during late-night and early-morning hours(People's vigilance is at its lowest during this period) often result in higher fatalities. The elderly and children are identified as vulnerable groups during earthquakes.

The implementation of annual earthquake disaster loss pre-assessment in Xinjiang demonstrates that estimating disaster scope, casualties, economic losses, and rescue demands requires localized models and must integrate region-specific critical factors. Therefore, following an analysis of key factors including seismic fortification standards for buildings, population distribution, earthquake-induced geological hazards, and scenario earthquakes that are involved in Xinjiang's annual earthquake disaster loss pre-assessment work.

We can conclude that in the future, the annual pre-assessment work in Xinjiang should be done better:

(1)According to the progress of Xinjiang's earthquake-safe housing projects, continuously optimize the structural ratio of regional residential buildings;

(2)According to the change of urban ground motion parameters, seismic zonation, and building fortification standards, the parameters of the building vulnerability model should be adjusted;

(3)We should pay great attention to the spatial variation of population migration with the seasonal alternation, and the difference in the rate of personnel in the room varies with different earthquake occurrence times;

(4)Under the characteristics of large dispersion and small aggregation of Xinjiang's population distribution, the scenario earthquake can be set directly below the densely populated area to constrain the upper limit of pre-assessment of casualties and rescue requirements;

(5)Sufficiently estimate potential casualties caused by earthquake geological disasters.

Key words: M7.1 Wushi earthquake, destructive earthquake, earthquake disaster loss pre-assessment, retrospective evaluation

摘要：

文中介绍了2024年1月23日新疆乌什7.1级地震的灾害情况, 将实际震害和抗震救灾投入的物资力量与其年度震灾损失预评估结果进行对比, 认为灾区面积、 人员伤亡、 转移安置人数及救灾需求等评估结果总体较好。文中回顾性检验了2015年以来新疆7次致人伤亡的破坏性地震, 其中3次6级地震的人员伤亡预评估与实际情况基本相当。此外, 对新疆年度震灾损失预评估涉及的建筑设防、 人口分布、 地震地质灾害、 设定地震等关键因素进行了分析讨论。文中获得的初步认识可用于指导今后新疆年度预评估工作。

关键词: 乌什7.1级地震, 破坏性地震, 震灾损失预评估, 回顾性检验