边界作用力改变与首都圈形变场变化

Variation of Displacement Field in Capital Region Due to the Change of Boundary Action

本文根据多种形变观测结果,研究了近期首都圈地区形变场出现的两次非线性变化过程,发现两次形变过程可能与边界作用力改变所引起的变化有关。分析认为:①两次形变过程均与大尺度形变场变化相关,这可能与大震所引起的边界动力作用改变有一定的关联;②2001年11月14日昆仑山口西8.1级大地震对首都圈形变场具有一定的影响,该地震的发生对首都圈地区应变积累具有一定的释放作用;③2004年出现的断层基线大幅度变化与大尺度形变场变化具有协调一致性特征,与首都圈地区强震前的局部应力场增强有所不同。

Two non-linear variations of deformation field in the Capital region were studied with the help of various deformation surveying data and the variations were found to be correlated to the change of boundary action. The analysis concludes： ①The two variations were correlated with the changes of large scale deformation field, which might be caused by the change of boundary action as a result of a large scale earthquake. ②The great earthquake （M = 8.1 ） occurred in the west of the Kunlun Mountain Pass on November 14, 2001 might affect the deformation field in the Capital region and the accumulated energy of strain field in Capital region were released partially by the great earthquake. ③ The variations of the cross fanlt short baseline in the Capital region in 2004, which differed from the strain field increasing before great earthquakes in this region, accorded with the variations of large scale deformation.