2012年云南宁蒗—盐源5.7级地震及震前异常分析  

Analysis for Basic Characteristic of Ninglang-Yanyuan MS5.7 Earthquake and its Precursory Anomaly in Yunnan in 2012

作　　者：钱晓东[1] 苏有锦[1] 李琼[1] 

机构地区：[1]云南省地震局,云南昆明650224

出　　处：《地震研究》2012年第4期455-463,共9页Journal of Seismological Research

基　　金：国家"十二五"科技支撑计划(2012BAK19B01)课题资助

摘　　要：2012年6月24日,云南省宁蒗县发生5.7级地震,宏观震中位于宁蒗县永宁乡永宁村一带,极震区烈度Ⅶ度,为NW向椭圆形状,地震造成3人死亡、25人重伤,直接经济损失50730万元。此次地震序列为主震—余震型,最大余震3.9级发生在6月26日,余震分布在主震北侧,呈近似NW向分布,与极震区烈度分布相一致,节面Ⅱ为主破裂面,主压应力P轴方位SE向,发震断裂为NW向的永宁断层。震前共出现8个异常项目12条异常,地震活动性异常4项,定点前兆异常5项,宏观异常3项,均为短临异常。An Ms5.7 earthquake occurred in Ninglang Country, Yunnan on Jun. 24, 2012, and its macroscopic epi- center was located at Yongning Village of Yongning Township in Ninglang Country. The intensity in the meizos- eismal area was VII and the distribution of isoseismic line is in elliptic with a long axis trending in nearly NW di- rection. The earthquake caused 3 deaths, 25 severe wounded and the direct economic loss of 507.3 million Yuan. The Ninglang Ms5.7 earthquake sequence was main shock-aftershock type and the largest ML3.9 after- shock occurred on Jun. 26. The aftershock distributed in the north side of the main shock in nearly NW direction and was consistent with the intensity distribution in the meizoseismal area. The main rupture surface was the nod- al plane I1, the direction of principal compressive stress P axis was in SE direction and the triggering seismic fault was the Yongning Fault in nearly NW direction. There were 12 precursory anomalies in 8 anomaly items, including 4 anomalies in seismometry, 5 fixed-point precursor anomalies and 3 macroscopic anomalies, which were short-term anomalies before Ninglang Ms5.7 earthquake.

关 键 词：宁蒗-盐源5 7级地震 震源机制 前兆异常 

分 类 号：P315.72[天文地球—地震学]