Reactivation mechanisms of the ancient Dahekou landslide in Hanzhong City, Shaanxi Province, China  

作　　者：NAN Kai LUO Yonghong XU Qiang ZHAO Bo SONG Huaying 

机构地区：[1]State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China [2]Key Laboratory of Mountain Hazards and Earth Surface Processes,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China

出　　处：《Journal of Mountain Science》2025年第4期1245-1260,共16页山地科学学报(英文)

基　　金：funded by the National Natural Science Foundation of China(Grant No.42077257)。

摘　　要：Ancient landslides with platform geomorphology occasionally reactivate,posing serious geohazards.On September 9,2021,persistent heavy rainfall triggered the reactivation of the Dahekou ancient landslide within a gently sloping geomorphology at the core of Zhangjiantan syncline in China's western Qinling-Daba Mountains.This event caused one death,damaged 80 houses,and blocked the Yushui River.This study reconstructs the sliding process of the Dahekou landslide and deciphers the complex landslide initiation mechanisms through field surveys,unmanned aerial vehicle(UAV)imagery analysis,drilling,electrical resistivity tomography(ERT)and small baseline subset–interferometric synthetic aperture radar(SBAS–InSAR)monitoring.We divide the sliding process of the Dahekou landslide into three stages.Two new landslides(#1 and#2)occurred at 18:30 on September 9,2021.Subsequently,the ancient landslide(#3)slid in the 230°direction at approximately 20:30 on September 9,2021,then changed the direction to 170°–240°at 22:30 on the same day,and moved in the direction of 300°at 10:00 the next day.Finally,the reactivated ancient landslide(#3)formed two partially sliding masses,with volumes of approximately 158×10^(4)m^(3)and 160×10~4 m^(3),along the directions of 170°–240°and 300°,respectively,damaging 80 houses and blocking the Yushui River.Field surveys suggest that new landslides#1 and#2 are rock landslides and soil landslides,respectively,with volumes of approximately 230×10^(4)m^(3)and 7.49×10~4 m^(3).Compared with the InSAR data,the new landslide#1 thrust the ancient landslide#3,with an uplift velocity rate of 22.68 mm/a at the rear edge,from September 2020–September 2021.An analysis of drill hole data reveals that the bedding in the landslide area has complex geological conditions,comprising mudstone prone to slipping with different degrees of weathering.Notably,the core of the Zhangjiatan syncline sits on the sliding bedding of the ancient landslide,contributing to a change in the sliding direction.This comp

关 键 词：Ancient landslide Landslide reactivation mechanism Evolutionary process GEOHAZARD 

分 类 号：P642.22[天文地球—工程地质学]