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2023年积石山Ms 6.2级地震同震地质灾害初步分析

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2023年12月18日,甘肃省临夏回族自治州积石山县发生Ms 6.2级地震,触发了大量同震地质灾害,亟需查明同震地质灾害的基本特征、发育分布规律和成因机制,为震后恢复重建与地质灾害防治提供支撑.本文基于多源高分辨率遥感解译和已有研究成果对比分析,初步揭示了此次地震地质灾害的基本特征和发育分布规律,并探讨了草滩村液化滑坡—泥流的成因机制.结果表明:此次地震Ⅶ度及以上烈度区内共发育1 535处同震地质灾害,主要为中小规模黄土滑坡和浅表层岩质崩塌,集中分布于黄土梁和黄土塬内冲沟两侧、单薄黄土梁两侧以及大型历史滑坡后壁等局部地形较陡峭的部位.地震因素控制了同震地质灾害的区域分布规律,而地形因素控制了同震地质灾害的局部分布规律.同震地质灾害在0.1~0.3 g震峰值加速度区域、发震断层下盘区域、南东坡向、30~60 m坡高范围、斜坡中部以上20~40 m范围分布数量最多.受广泛关注的草滩村"砂涌"灾害本质是饱水黄土在地震作用下发生的液化滑坡.2016年完成的填沟造地工程改变了滑源区地表和地下水流通条件,地下水通道被堵塞,导致地下水位抬升和下部土体饱和可能是该处发生液化滑坡的重要原因.
Preliminary analysis of the coseismic geohazards induced by the 2023 Jishishan Ms 6.2 earthquake
On December 18,2023,an earthquake with a magnitude of Ms 6.2 occurred in Jishishan County,Gansu Province,triggering a large number of coseismic geohazards.As such,there is an urgent need to identify the characteristics,distribution patterns,and mechanisms of the coseismic geohazards caused by this earthquake to provide support for post-earthquake recovery and reconstruction.Based on multisource high-resolution remote sensing interpretation and a comparative analysis of existing research results,the essential characteristics and distribution patterns of the coseismic geohazards are preliminarily revealed,and the mechanism of the liquefaction landslide mudflow in Caotan Village is explored.The results show that a total of 1 535 coseismic geohazards developed in areas with a seismic intensity of Ⅶ or above during the earthquake,mainly consisting of small-and medium-scale loess landslides and shallow rockfalls.These geohazards were mainly distributed on both sides of loess beams and loess plateau gullies,on both sides of thin loess beams,and on the back walls of large historical landslides where the terrain was steep.It is found that earthquake factors controlled the regional distribution pattern of coseismic geohazards,while terrain factors controlled the local distribution pattern of coseismic geohazards.We find that the coseismic geohazards had the highest distribution in areas of peak acceleration of 0.1-0.3 g,footwall areas around the seismic fault,areas where the slope points in a southeastern direction,areas with slope heights of 30-60 m,and areas 20-40 m above the middle of the slopes.The sand surge disaster in Caotan Village,which caused great concern throughout all of society,was a liquefaction landslide caused by saturated loess reacting to earthquake action.This disaster may be have been inadvertently exacerbated by the"gully filling and land reclamation project"that completed in 2016,which changed the surface and groundwater flow conditions in the sliding source area.Additionally,groundwater channels were blocked,causing the groundwater level to rise and the lower soil to saturate,which may be an essential reason for the liquefaction landslides in this area.

Jishihan earthquakecoseismic geohazardsdistribution patternloess landslideliquefied landslide-mudflow gully filling and land reclamation project

李为乐、许强、李雨森、单云锋、韦春豪、巨袁臻、郁文龙、王运生、卢佳燕

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地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都 610059

应急管理部滑坡灾害风险预警与防控实验室,成都 610059

中国地质调查局 成都地质调查中心(西南地质科技创新中心),成都 610081

积石山地震 同震地质灾害 分布规律 黄土滑坡 液化滑坡—泥流 填沟造地工程

国家重点研发计划四川省重点研发项目地质灾害防治与地质环境保护国家重点实验室自主研究课题

2021YFC30004012023YFS0435SKLGP2022Z007

2024

成都理工大学学报(自然科学版)
成都理工大学

成都理工大学学报(自然科学版)

CSTPCD北大核心
影响因子:1.596
ISSN:1671-9727
年,卷(期):2024.51(1)
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