Intricate Fault Systems in Longmenshan Structural Belt's Northern End:Exploring Structural Evolution and Seismic Rupture Behavior in the Eastern Tibetan Plateau  

作　　者：Hanyu Huang Renqi Lu Dengfa He Jinliang Gao Weikang Zhang Lingyu Kang 

机构地区：[1]State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China [2]State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China [3]College of Energy Resources,China University of Geosciences,Beijing 100083,China [4]PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China

出　　处：《Journal of Earth Science》2025年第1期250-265,共16页地球科学学刊(英文版)

基　　金：supported by the National Key Research and Development Project of China(No.2021YFC3000600)。

摘　　要：The Longmenshan structural belt on the eastern edge of the Tibetan Plateau experienced the impactful Mw7.92008 Wenchuan Earthquake,causing a 350 km surface rupture.Traditional models attribute this to the Beichuan and Pengguan faults,but our research reveals a complex fault system at the northern end,with inconsistencies in surface rupture,aftershock distribution,and focal mechanisms.We integrate shallow geology,active source seismic reflection,and magnetotelluric profiling to establish a deep structural model for the northern end of the Longmenshan structural belt.This area exhibits dominant reverse thrust nappe tectonics,and analyzing the tectonic evolution history provides insights into deformation propagation from the orogenic belt toward the Sichuan Basin.Focal mechanism analysis and relocated aftershock data reveals two distinct types of seismogenic structures in the northern end of the Longmenshan structural belt.In the middle to northern segments,the reverse fault type is attributed to reactivated pre-existing faults.Conversely,at the northern end,the strike-slip fault type originates from high-angle co-seismic rupture cutting through pre-existing reverse faults.This study enhances our understanding of fault complexity and seismic mechanisms in the northeastern Longmenshan structural belt,providing new insights into regional tectonics.

关 键 词：Longmenshan structural belt fault system structural evolution TECTONICS EARTHQUAKES focal mechanism 

分 类 号：P315[天文地球—地震学]