1976年唐山7.8级地震前地下水位变化与地震成核过程的关系  

Groundwater level changes before the 1976 Tangshan M_(S)7.8 earthquake and its relation with the earthquake nucleation process

作　　者：马玉川[1,2] 晏锐 王广才[2] 余怀忠[1] 黎明晓[1] 丁志华[3] 张子广[3] MA YuChuan;YAN Rui;WANG GuangCai;YU HuaiZhong;LI MingXiao;DING ZhiHua;ZHANG ZiGuang(China Earthquake Networks Center,Beijing 100045,China;School of Water Resources&Environment,China University of Geosciences,Beijing 100083,China;Hebei Earthquake Agency,Shijiazhuang 050021,China)

机构地区：[1]中国地震台网中心,北京100045 [2]中国地质大学(北京)水资源与环境学院,北京100083 [3]河北省地震局,石家庄050021

出　　处：《地球物理学报》2022年第4期1325-1335,共11页Chinese Journal of Geophysics

基　　金：国家重点研发计划(2018YFC150330505);国家自然科学基金(U2039205);地震科技星火计划项目(XH21046Y);国家重点研发计划(2018YFE0109700)联合资助.

摘　　要：探索地震成核过程的野外观测证据对地震成核研究及地震短临预测实践具有重要的科学意义和现实意义.本文收集了1976年唐山7.8级地震发震断层附近密集的地下水位观测资料,回溯了唐山7.8级地震发生前后的地下水位变化,对比分析了地下水位变化和地震成核的相关研究结果.结果表明,唐山7.8级地震前后地下水位存在显著的中期、短期、临震和震后变化;中期水位下降速率变缓可能与地震成核后期阶段的核心弱化区收缩有关;短期水位加速下降可能是核心弱化区扩容所造成;而临震大幅上升或波动可能与成核区周围应力快速上升相关.地震成核理论可以较为合理的解释唐山地震前地下水位变化的成因,在一定程度上为地震成核野外观测提供了实际震例.It is of great scientific and practical significance to explore the field observation evidence of earthquake nucleation process for the study of earthquake nucleation and the practice of earthquake prediction.In this study,observation data of the groundwater level before and after the 1976 Tangshan M_(S)7.8 earthquake in the vicinity of the seismogenic fault were collected,and the changes of the groundwater level before the Tangshan M_(S)7.8 earthquake were retrospectively reviewed,analyzed,and compared with theoretical results of earthquake nucleation.The results show that significant groundwater level changes occurred in mid-term,short-term and impending term before the M_(S)7.8 Tangshan earthquake.There is a certain correlation between the slow rate of water level decline in the mid-term stage and the contraction of the weakening-zone core in the late stage of the nucleation,between the accelerated rate of water level decline in the short-term stage and the dilatancy in the weakening-zone core,and between the sharp rise or fluctuation of the groundwater level in the impending term and the rise of stress around the weakening-zone core.The theory of earthquake nucleation can reasonably explain the cause of the change of groundwater level before the Tangshan earthquake and provide practical examples for the field observation of earthquake nucleation to some extent.

关 键 词：唐山7.8级地震 发震断层 水位变化 地震成核 核心弱化区 亚失稳 

分 类 号：P315[天文地球—地震学]