2013年岷县漳县M_S6.6地震前后南北地震带北段面波速度变化特征  

Variation Characteristics of Surface Wave Velocity along North Segment of North-South Seismic Belt before and after 2013 Minxian—Zhangxian M_S6.6 Earthquake

作　　者：严珊[1] 杨立明[1] 周龙泉[2] 张辉[1] 王芃[3] 

机构地区：[1]中国地震局兰州地震研究所,甘肃兰州730000 [2]中国地震台网中心,北京100045 [3]中国地震局地震预测研究所,北京100035

出　　处：《地震工程学报》2016年第3期423-430,共8页China Earthquake Engineering Journal

基　　金：中国地震局地震科技星火计划攻关项目(XH15042);甘肃省科技计划(145RJZA186);国家自然科学基金项目(41304048);"十二五"国家科技支撑项目(2012BAK19B02-01)

摘　　要：基于南北地震带北段94个固定地震台站2013年1—9月的连续波形资料,利用背景噪声方法和层析成像技术反演该地区在2013年7月22日甘肃岷县漳县MS6.6地震前后不同时间段、两个月相同时间窗长的瑞利面波速度结构与波速演化。相速度成像结果表明:岷县漳县地震前5—6月相对于3—4月,临潭—宕昌断裂带及周边地区出现了波速降低的现象,而震后8—9月相对于5—6月波速逐渐恢复升高,这说明在岷县漳县地震前两个月出现了波速低值异常,并且在低速异常区域的边界处发生了此次地震。Based on background noise and tomography methods,in this paper,we investigated the continuous waveform records of 94 fixed seismic stations in the northern segment of the north-south seismic belt from January to September,2013.In doing so,we obtained the velocity struc-ture and evolution of the Rayleigh waves of this area,at different times in the same two-month period before and after the Minxian—ZhangxianMS6.6 earthquake on July 22,2013.The phase ve-locity tomography results show that before the earthquake,in May-June,the wave velocity along the Lintan—Tanchang fault zone and its surrounding areas reduced relative to that in March-April.However,after the earthquake,in August-September,the wave velocity along the Lintan—Tanchang fault zone and its surrounding areas was restored by rising to the level of May-June. These results indicate that in the two months before the Minxian—Zhangxian MS6.6 earthquake, the velocity exhibited low-value anomalies,and the earthquake occurred at the boundary of the low-velocity anomaly region.

关 键 词：南北地震带北段 甘肃岷县漳县MS6.6地震 背景噪声 层析成像 速度结构 临潭—宕昌断裂带 波速低值异常 祁连山中段 

分 类 号：P315.3[天文地球—地震学]