利用地震和爆破资料反演宁夏及邻区浅层三维速度结构

Inversion of earthquake and explosion data for 3-Dvelocity structure in Ningxia and adjacent region

  • 摘要: 将有限差分正演及LSQR反演方法应用到宁夏及邻区,利用该区2003——2009年7年间的地震和爆破记录,经过重新细致分析,得到了具有4个以上台站清楚记录到初至波Pg和Pn到时的地震426次、爆破52次,剔除到时离散较大的数据后共有2788条记录.获得了不同深度的速度平面分布图像以及不同位置的深度速度剖面图像.得出深度0——5 km的平均速度约为5.1 km/s,深度5——25 km的平均速度约为5.9 km/s,深度25——30 km的平均速度约为6.4 km/s;浅层低速层主要分布在银川地堑、中卫清水河盆地,高速层主要分布在银川地堑西部的贺兰山区. 此结论与该地区地质结构相符.深层高速层在中卫——同心断裂带一带最为显著,低速层主要分布在银川地堑及以西部分地区、固原清水河断裂带等.

     

    Abstract: We applied the finite difference and LSQR algorithm inversion in Ningxia and adjacent region .Using 2003-2009 7 years 426 earthquakes and 52 exploions Pg and Pn first arrival data,Excluding discrete large data remain 2788 records ,we obtained distribution of the image plane at different depths and different positions of the depth direction, velocity profile images. Combined with geological data and previous studies draw conclusions as follow: 0-5km depth average velocity 5.1 km/s, 5-25km depth average velocity 5.9 km/s, 25-35km depth average velocity 6.4 km/s; In shallow low-speed is distributed in Yinchuan graben basin, and Qingshui river basin in Zhongwei and High is distributed in Helan mountain area. In the deep high-speed is distributed in Zhongwei-Tongxin fault zone, Low is mainly distributed in the yinchuan graben and west parts, guyuan qingshui river fault zone.This conclusion is basically consistent with previous studies.

     

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