中文摘要：

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.

英文摘要：

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.