Spatial structural characteristics of the Deda ancient landslide in the eastern Tibetan Plateau:Insights from Audio-frequency Magnetotellurics and the Microtremor Survey Method  

作　　者：Zhen-dong Qiu Chang-bao Guo Yi-ying Zhang Zhi-hua Yang Rui-an Wu Yi-qiu Yan Wen-kai Chen Feng Jin 

机构地区：[1]Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China [2]Faculty of Engineering,China University of Geosciences,Wuhan 430074,China [3]Key Laboratory of Active Tectonics and Geological Safety,Ministry of Natural Resources,Beijing 100081,China [4]Research Center of Neotectonism and Crustal Stability,China Geological Survey,Beijing 100081,China [5]China Water Resources Beifang Investigation,Design and Research Co.Ltd.,Tianjin 300222,China

出　　处：《China Geology》2024年第2期188-202,共15页中国地质（英文）

基　　金：supported by the National Natural Science Foundation of China(42372339);the China Geological Survey Project(DD20221816,DD20190319)。

摘　　要：It is of crucial importance to investigate the spatial structures of ancient landslides in the eastern Tibetan Plateau’s alpine canyons as they could provide valuable insights into the evolutionary history of the landslides and indicate the potential for future reactivation.This study examines the Deda ancient landslide,situated in the Chalong-ranbu fault zone,where creep deformation suggests a complex underground structure.By integrating remote sensing,field surveys,Audio-frequency Magnetotellurics(AMT),and Microtremor Survey Method(MSM)techniques,along with engineering geological drilling for validation,to uncover the landslide’s spatial feature s.The research indicates that a fault is developed in the upper part of the Deda ancient landslide,and the gully divides it into Deda landslide accumulation zoneⅠand Deda landslide accumulation zoneⅡin space.The distinctive geological characteristics detectable by MSM in the shallow subsurface and by AMT in deeper layers.The findings include the identification of two sliding zones in the Deda I landslide,the shallow sliding zone(DD-I-S1)depth is approximately 20 m,and the deep sliding zone(DD-I-S2)depth is 36.2-49.9 m.The sliding zone(DD-Ⅱ-S1)depth of the DedaⅡlandslide is 37.6-43.1 m.A novel MSM-based method for sliding zone identification is proposed,achieving less than 5%discrepancy in depth determination when compared with drilling data.These results provide a valuable reference for the spatial structural analysis of large-deepseated landslides in geologically complex regions like the eastern Tibetan Plateau.

关 键 词：Ancient landslide Remote sensing Audio-frequency Magnetotellurics(AMT) Microtremor Survey Method(MSM) Geological drilling engineering Spatial structure Tibetan Plateau Geological hazard survey engineering 

分 类 号：P631[天文地球—地质矿产勘探] P642.22[天文地球—地质学]