【摘要】 地震危险区断层的应力状态变化及其精确测量一直是地球物理学关注的热点问题之一,主动震源探测技术的发展为解决上述问题带来了可能.汶川大地震后,结合汶川地震断裂带科学钻探,在四川省绵竹市九龙镇——跨越龙门山断裂带前山断裂,利用10 t精密控制人工震源进行了连续监测试验,在试验观测期间的2009年6月30日凌晨2时3分,当地发生了M_s 5.6级地震,地震前后观测数据的对比分析表明,该地震发生前后,穿过断裂带的直达S波走时发生了时延为5～9 ms的微弱变化,射线路径上的平均波速相对下降了约0.3%,该时延主要是由地震同震效应引起的断裂带内应力调整和物性变化造成的.所使用的精密控制人工震源性能稳定,适于开展断层监测.这一结果对于发展断裂带主动震源动态监测技术具有重要意义.更多还原

【Abstract】 The stress status change and its exact measurement of the fault zone has been a hotspot in geophysics.After the Wenchuan earthquake,we carry out continuous monitoring across the range-front fault of the Longmenshan fault zone,using a 10-ton precisely controlled active source.An M_s5.6 earthquake happened at 02:03 in the morning of June 30th 2009 near the experimental site,and the direct S wave velocity across the fault zone occurred a slight change by comparative analysis of data before and after the earthquake.Time delay is up to 5～9 ms,the S wave velocity decreased ～0.3%.The time delay was mainly caused by the stress change within the fault zone due to the earthquake.更多还原