积石山地震诱发金田-草滩村滑坡-泥流灾害链过程与成因

A preliminary analysis of the process and cause of the Jintian-Caotan landslide-mudflow hazard chain induced by the Jishishan Earthquake

2023年12月18日23:59在甘肃省积石山保安族东乡族撒拉族自治县发生6.2级地震,地震在青海省民和回族土族自治县中川乡金田及草滩村引发了一处滑坡-泥流灾害链事件.利用无人机摄影测量、激光雷达扫描和电阻率层析成像等技术,结合详细现场调查及访问对该灾害链事件展开勘查分析,发现地震诱发台塬面下饱水黄土层液化是本次灾害链的主要原因.该饱水黄土层的形成与区域长期的农业灌溉有关,冬季地下水出口被冻结导致的地下水位上涨增加了液化的可能性.黄河上游类似中川乡地质地貌条件的引水灌溉区域有很多,未来地震条件下发生区域液化滑坡-泥流灾害链的风险性极高.

On December 18,2023,at 23:59,a 6.2 magnitude earthquake occurred in Jishishan County,Gansu Province.This earthquake triggered a landslide-mudflow hazard chain in Jintian and Caotan villages of Zhongchuan Township,Minhe County,Qinghai Province.We conducted a detailed field survey of the hazard chain using unmanned aerial vehicle photogrammetry,laser scanning,resistivity tomography imaging and interview with local people.We find that the earthquake induced liquefaction of the saturated loess layer below the platform surface was the main cause of this hazard chain.The formation of this saturated loess layer is related to long-term agricultural irrigation in the region,and the rise in groundwater level due to the freezing of underground water outlets in winter also increased the possibility of liquefaction.Since there are many similar geological and geomorphological conditions in the upstream of the Huanghe River,where irrigation is carried out,there is a high risk of landslide-mudflow hazard chain occurrence in this region under future earthquake conditions.