2014年山西平遥M_S4.1地震前后重力场变化特征分析  

Analysis on Dynamic Variation Characteristic of Gravity Field before and after Pingyao M_S4.1 Earthquake in 2014

作　　者：贾宇鹏[1] 秦建增[1] 李真[1] 黎哲君[2] 檀玉娟[1] 冯建林[1] 

机构地区：[1]中国地震局地球物理勘探中心,河南郑州450002 [2]安徽省地震局,安徽合肥230031

出　　处：《地震研究》2015年第3期377-383,共7页Journal of Seismological Research

基　　金：中国地震局地球物理勘探中心青年基金项目(YFGEC2014006);中国地震局震情跟踪合同制项目(2014010204)共同资助

摘　　要：利用2012-2014年山西省绝对重力和流动重力观测资料,平差计算得到该时间段重力场变化值,分析区域重力场演化特征与2014年4月平遥MS4.1地震的关系。研究发现：（1）地震发生前研究区域出现了区域性的重力异常变化,在震中附近产生局部重力异常变化,形成了与活动断裂走向基本一致的重力变化高梯度带,这可能预示着与地震发生相关的构造运动或应力增强作用。（2）地震前后研究区重力场累积变化表现为应力场增强—持续增强—局部运动受阻超过临界值—能量突然释放,震后重力场变化恢复到平稳状态。Using the observation data of absolute and flow gravity measurements in Shanxi region from 2012 to 2014,we obtained gravity field and its dynamic variations by adjustment,and analyzed the spatial-temporal evaluation of the regional gravity field and their relationship to Pingyao MS4. 1 earthquake. The research result mainly show s that：（ 1） Before Pingyao MS4. 1 earthquake,there appeared the regional gravity anomaly in the study region and the local gravity anomaly near the epicenter. The high gradient belt of gravity change formed in accordance with the strike of the active tectonic fault,which could predict the tectonic activity or stress enhancing related with the preparation and occurrence of the earthquake.（ 2） Before and after the earthquake,the patterns of the gravity field accumulation variation appeared the follow ing process in the study area： the regional stress field strengthened first,then continued to strengthen, and the local movement of it was locked somew here, the earthquake came about during the energy exceeded the critical value. Finally,the gravity field change was back to the steady state after the earthquake.

关 键 词：重力场 联合平差 动态变化 平遥地震 

分 类 号：P315.72[天文地球—地震学]