摘要
2023年12月18日甘肃省积石山县发生了M_(s)6.2地震,与以往同等级地震相比,其表现出“同震重灾”特征和引发了特殊流滑地质灾害。通过现场震害调查、走访受灾群众和搜集地质资料及相关文献,重点探讨了本次地震的发震背景和孕育地质条件,对比了宏观烈度分布特征及与仪器烈度差异,统计了不同民居房屋的典型震害特征及所占比例,调查了造成人员伤亡的主要成因;踏勘了次生流滑灾害宏观特征,对揭示其成因与触发条件提出了若干关键问题。结果表明:宏观与仪器烈度具有较为明显差异,原因主要为地形地质条件复杂、不同乡镇经济发展水平与房屋抗震设防能力差异及烈度仪布设缺乏统一标准;强震观测记录地表加速度明显大于2021年漾濞M_(s)6.4地震,烈度Ⅵ、Ⅶ、Ⅷ区面积分别为2022年芦山M_(s)6.1地震的2.3、1.5、2.5倍,为造成同级地震重灾的一个重要成因;泥流掩埋摧毁房屋、炕头相连淋浴间隔墙倒塌及地震发生在深夜是造成本次地震人员伤亡重的重要因素。流滑区域长约3 km,前后高程差约85 m,总面积约39万m^(2),漫出地面约3 m高,塌陷区残留若干孤岛,其可能为长期农田灌溉、地下水体富集、地震主振方向与泥流运动和天然沟谷方向相同等外在因素和黄土湿陷、土体液化等内在机理综合诱发,具体成灾诱因、物理机制和触发条件需多种手段联合验证。调查证明,按照抗震设防标准进行房屋建设和既有建筑加固,强化农村居民防震减灾意识和应急避难知识,是减轻地震造成人员伤亡的有效措施。
On December 18,2023,a M_(s)6.2 earthquake struck Jishishan County,Gansu Province,showing the characteristics of"similar seismic magnitude but heavy disaster"and triggering special flowslide geologic hazards compared to previous earthquakes of the same magnitude.Through survey-ing the on-site seismic damage,visiting the quake-affected people,collecting geological data and con-sulting related literature,the seismogenic background and geological conditions of this earthquake were investigated.The comparison of the distribution differences between instrumental intensity and macro intensity,the statistics on the typical seismic damage characteristics of different residential houses and their proportion,and the investigation on the main causes of casualties were also carried out.The macro features of secondary flowslide disasters were detected,and some key questions about the cause and triggering of the earthquake were proposed.The results show that there are obvious differences between the instrumental and macroscopic intensities,mainly due to the complex topographic and geological conditions,the differences in economic development levels and seismic fortification capabilities of buildings in different townships,and the lack of a consistent standard for the deployment of the intensity instrumentation;the surface acceleration recorded in the strong-seismic observation is obviously greater than that in the 2021 Yangbi M_(s)6.4 earthquake,and the areas with intensitiesⅥ,Ⅶ,andⅧare 2.3,1.5,and 2.5 times of those in the 2022 Lushan M_(s)6.1 earthquake,respectively.These are important reasons that cause severe damage although having similar magnitude;the main factors causing heavy casualties in this earthquake include the burial and destruction of houses by mud-slides,the collapse of shower walls connected to the kang,and the occurrence of the earthquake in the late night.The flowslide area is about 3 km long,with an elevation difference of about 85 m between the front and back,and an area of about 390,000 m^(2).It spread out to a height of about 3 m above the ground,leaving behind several isolated islands in the collapse area,which may be triggered by a com-bination of external factors such as long-term irrigation of farmland,enrichment of the underground water,and the direction of the seismic main vibration being the same as that of the flowslide move-ment and the natural valley direction,and the intrinsic mechanisms such as wet subsidence of loess,liquefaction of the soil,and so on.The specific causes of the disaster,the physical mechanisms,and the triggering conditions need to be verified jointly by various means.The survey proved that building construction and existing building reinforcement in accordance with seismic fortification standards and strengthening the awareness of earthquake prevention and mitigation and the knowledge of emergency evacuation of rural residents are effective measures to reduce the casualties caused by earthquakes.
作者
蒋伟
王永志
袁晓铭
汤兆光
陈龙伟
聂桂波
李兆焱
张昊宇
JIANG Wei;WANG Yongzhi;YUAN Xiaoming;TANG Zhaoguang;CHEN Longwei;NIE Guibo;LI Zhaoyan;ZHANG Haoyu(Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Key Laboratory of Earthquake Disaster Mitigation,Ministry of Emergency Management,Harbin 150080,China)
出处
《防灾减灾工程学报》
CSCD
北大核心
2024年第1期1-11,共11页
Journal of Disaster Prevention and Mitigation Engineering
基金
中国地震局工程力学研究所基本科研业务费与专项项目(2023B08)
黑龙江省自然科学基金项目(LH2023E019)资助。
关键词
积石山6.2级地震
震害调查
地震烈度
流滑灾害
Jishishan 6.2 magnitude earthquake
seismic hazard investigation
seismic intensity
flow-slide
