The Tongliao MS5.3 Earthquake and Its Foreshock Determination

作     者：Wang Shubo Zhuoli Getu Li Juan 

作者机构：Earthquake Agency of Inner Mongolia Autonomous RegionHohhot 010010China 

出 版 物：《Earthquake Research in China》 (中国地震研究（英文版）)

年 卷 期：2018年第32卷第3期

页      面：344-354页

核心收录：

学科分类：070801[理学-固体地球物理学] 07[理学] 0708[理学-地球物理学] 

基　　金：Science and Technology MajorProject of Inner Mongolia Autonomous Region entitled“Research development and promotion of earthquake prediction and early warning technology in key areas”.Seismic Regime Tracking Project of CEA No.2018010124 

主　　题：Tongliao M S5.3 earthquake HypoDD location CAP Focal mechanism similarity Foreshock determination 

摘      要：Taking the 2013 Tongliao MS5. 3 earthquake as a research subject, on the basis of statistical analysis of earthquake sequence using the HypoDD location method and focal mechanism solutions,the paper analyzes and discusses the relationship between the ML4. 4 and MS5. 3 earthquakes. The results show that the Tongliao MS5. 3 earthquake occurred under the background of medium-small earthquakes long-term quiescence and short-term enhancement in the epicentral area. The results of accurate seismic location shows that the Tongliao MS5. 3 earthquake sequence is distributed in the NW direction,extending 10 km,and the ML≥3. 0 aftershocks are concentrated south of the mainshock. The distance between the MS5. 3 mainshock and the ML4. 4 foreshock is about 1. 8 km,with a focal depth of 7. 208 km and 7. 089 km,respectively,their focal location is very close,and may have occurred on the same fault plane. The results of focal mechanism shows that the Tongliao MS5. 3 earthquake is of the strike-slip type,the focal mechanism of aftershocks are disordered,and with time lapse,the type is changed from strike-slip to thrust and normal faulting. The bigger foreshocks had similar focal mechanism and were all normal fault types,which exhibits to some extent,an obvious crustal medium anisotropy in the epicentral area before macroscopic rupturing,as represented by alignment fractures,with stress action enhanced,thisconsistencyof seismic precursor regime would gestate the mainshock. According to the characteristics of temporal-spatial distribution of earthquake sequence and similarity of focal mechanism,we judge that the Tongliao MS5. 3 earthquake sequence is a foreshock-mainshock-aftershock type.