Identification of seismic activity and basin inversion based on soft-sediment deformation structures:an example from SE Korea  

作　　者：Jinhyun Lee Sambit Prasanajit Naik Ho-Seok Choi Jinhyeon So Donghwa Yun Young-Seog Kim 

机构地区：[1]Division of Earth Environmental System Sciences,Pukyong National University,Busan 48513,Republic of Korea [2]Active Fault and Earthquake Research Institute,Pukyong National University,Busan 48513,Republic of Korea [3]Department of Geology and Research Institute of Natural Science,Gyeongsang National University,Jinju 52828,Republic of Korea

出　　处：《Episodes》2024年第3期595-610,共16页地质幕(英文版)

基　　金：supported by a grant(2022-MOIS62-001(RS-2022-ND640011))from the National Disaster Risk Analysis;Management Technology in Earthquake funded by the Ministry of Interior and Safety(MOIS,Korea).

摘　　要：Deformed soft-sediment deformation structures(SSDS)can indicate polyphase deformation events and provide valuable insights into the inversion process of a basin.Herein,we present the Miocene–Quaternary deformation inversion history of the Bomun sub-basin in the Gyeongju area of SE Korea.The inferred ENE compression direction(σHmax)based on paleostress analysis of the fault system,displacing Miocene sediments and SSDS,corresponds to the current stress field.The widespread occurrence of clear liquefaction structures and the vertical repetition of SSDS indicate substantial seismic activity during the basin opening stage.Brittle deformation features observed at both outcrop-and microstructural-scale along the faults suggest a reactivation as reverse faulting associated with a tilting process.The tectonic history of the study area is distinguished by SSDS associated with seismic activity,and reverse faulting associated with inversion process under ENE orientedσHmax.The Environmental Seismic Intensity Scale(ESI-07)based on the SSDS indicates seismic intensity of IX-X,which might be related with the opening of the Bomun sub-basin.Therefore,detailed analyses of SSDS could provide valuable insights on the dynamics of local geology and contribute to further extensive research on seismic hazards and basin inversion.

关 键 词：Miocene Quaternary seismic activity polyphase deformation events basin inversion soft sediment deformation structures clear liquefaction struc paleostress analysis 

分 类 号：P315.2[天文地球—地震学] P315[天文地球—固体地球物理学]