岷县漳县M_S6.6地震前区域形变场的特征  

Characteristics of the Regional Deformation Field before Minxian—Zhangxian M_S6.6 Earthquake

作　　者：杨博[1] 朱爽[1] 杨国华[1] 周伟[1] 冯胜涛[1] 陈欣[1] 

机构地区：[1]中国地震局第一监测中心,天津300180

出　　处：《地震》2014年第2期115-123,共9页Earthquake

基　　金：地震行业科研专项(201208006;301308009);科技支撑项目(2012BAK19B01-2)资助

摘　　要：利用1999—2007、2009—2011年的流动GNSS观测资料和2010.5年以来的连续GNSS观测资料与处理结果,分析了2013年7月岷县漳县MS6.6地震区域水平形变场及其变化。获得的结果显示:①岷县漳县MS6.6地震发生在地壳运动的转折区域内,该区域运动量级较小、水平形变也相对较弱;②发震区带1999—2007年最大主应变为正负应变的过渡带,2009—2011年最小主应变也为正负应变的过渡带,1999—2007年则相对较大;③发震区带最大剪切应变相对较小,同时也是旋剪形变左、右旋的转化区;④连续站的结果显示该地震是在几乎纯逆冲构造活动背景下发生的,同震形变较小,其范围在距震中数十公里的半径内;⑤震前未发现GNSS观测结果中存在短临异常,但存在着趋势性形变亏损异常等。Using the mobile GNSS observations of 1999--2007, 2007--1999, and continu- ous GNSS observations since 2010.5 and their processing results, horizontal deformation field and its changes before the Minxian--Zhangxian Ms6. 6 earthquake have been ana- lyzed. We found that （1） the Minxian--Zhangxian Ms6.6 earthquake occurred in the tran- sition area ofcrust movement, in which movement magnitude is smaller and horizontal de- formation is relatively weak; （2） the maximum principal strain of this earthquake zone in 1999--2007 is transition zone from positive to negative strain, the minimum principal strain in 2009--2011 also is transition zone from positive to negative strain, which is rela- tively large in 1999--2007; （3） the maximum shear strain of this earthquake zone is rela- tively small, and also is transformation zone for the left and right rotary; （4） the result of the continuous station shows that the earthquake happened in a almost pure thrust tectonic regime, the coseismic deformation is small, its scope is in the range of 10 kilometers from the epicenter; （5） there are no anormaly found in short-time GNSS observations before the earthquake, but there is anabnormaldeformation deficit in trend.

关 键 词：区域水平形变 青藏高原东北缘 形变异常 岷县漳县MS6 6地震 

分 类 号：P315.7[天文地球—地震学]