[关键词]
[摘要]
通过联合使用固定台站和流动台站资料,对2010年5月~2011年7月发生在云南地区的7127个地震进行重新定位。考虑到速度模型对定位结果的影响,用VELEST方法获得云南地区走时残差均方根最小的一维P波速度模型,基于反演模型用双差法对地震进行重新定位,得到5836个地震的定位结果。结果表明,云南地区发震层主要位于中上地壳,且滇西地区震源深度相对较深。用精定位后的地震目录计算云南地区b值,从b值空间分布特征可以看出,b值随深度逐渐减少,且在9~10km深度时,b值变化最为明显,可能表明云南地区中强震孕震层主要位于9km以下;同时,盈江5.8级地震序列b值的三维空间分布显示,主震发生在高低b值的过渡带。
[Key word]
[Abstract]
We relocated 7172 earthquakes occurring in the Yunnan area from May,2010 to July,2011 by jointly using the permanent and temporary station records data. Considering the impact of velocity model,we first obtained a 1-D mininum P velocity model with the VELEST method. And then we got 5836 epicenter results by applying the double-difference method,and the resluts show that the seismogenic layer is basically located in the upper and middle crust,and the focal depth is more deeper in western Yunnan. We caculate the b-value of the Yunnan area using the relocated earthquake catalogs,and some new recognitions were achieved:the b-value was gradually reduced with depth,particularly at the depth of 9~10km;and the b-value 3-D distribution of the Yingjiang MS5.8 earthquake sequences showed that the main shock was in the transition zone with high and low b-value.
[中图分类号]
[基金项目]
科研院所基本科研业务专项(ZDJ2013-12)和国家自然科学基金项目(41304037)资助