Numerical simulation of tectonic stress and strain rate fields in the northeastern margin of the Tibetan Plateau in association with major fault zones

作     者：Shuhong ZHOU Huai ZHANG Yunqiang SUN Caibo HU Yaolin SHI 

作者机构：Key Laboratory of Computational GeodynamicsUniversity of Chinese Academy of SciencesBeijing100049China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai519080China Beijing Yanshan Earth Critical Zone National Research StationUniversity of Chinese Academy of SciencesBeijing101408China College of Transportation and Civil EngineeringFujian Agriculture and Forestry UniversityFuzhou350002China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2023年第66卷第10期

页      面：2353-2367页

核心收录：

学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 0818[工学-地质资源与地质工程] 0837[工学-安全科学与工程] 

基　　金：supported by the National Natural Science Foundation of China for Distinguished Young Scholars(Grant Nos.U2239205,41725017) the National Key Scientific and Technological Infrastructure Project。 

主　　题：Northeastern margin of the Tibetan Plateau Finite element model Stress and strain fields Seismic hazard 

摘      要：A series of large strike-slip and thrust faults have developed in the northeastern margin of the Tibetan Plateau since the Late Cenozoic,with strong and active tectonic activity and frequent occurrences of large earthquakes.Modulation of regional tectonic stress distribution,strain fields,and seismic hazards has not been well studied.This study introduces a three-dimensional viscoelastic finite element numerical model to calculate crustal stress and strain rate fields under current tectonic loading.The preliminary results show that the direction of the horizontal principal compressive stress rate and compressive horizontal principal strain rate in the northeastern margin of the Tibetan Plateau rotate clockwise as a whole,and this rotation is more significant in the southeast direction because of the block of the Alxa and the Ordos blocks.The NE-SW horizontal principal compressive stress rate and SE horizontal tensile stress rate dominate the entire study region.The maximum value of the horizontal principal compressive strain rate at a depth of 0 km in the model is approximately 4×10^(-8)yr^(-1)near the East Kunlun fault and is smaller in the stable Alxa and Ordos blocks at approximately 1×10^(-8)yr^(-1).The calculated regional stress state is in good agreement with the actual focal mechanism solution,indicating that strike-slip and thrust stress fields dominate the northeastern margin of the Tibetan Plateau.The Altyn Tagh,East Kunlun,and Haiyuan faults demonstrate that the maximum shear strain rate gradually decreases eastward,and the decrease in the maximum shear strain rate value is absorbed by orogenic uplift and crustal shortening at its boundaries.The western section of the Altyn Tagh fault,west-to-middle sections of the East Kunlun fault,and west-to-middle sections of the Haiyuan fault will have high seismic hazards in the future.