通过格林第二内部积分公式导出地面位移与地壳内应力变化的关系,分析和讨论利用地面位移变化速率来计算地球内应力场变化的可能性和计算方法;最后,采用2001-2005和2004-2007年间在中国四川地区观测的GPS位移场速率数据,对汶川地震区震前地壳内深度为15km处的最大主应力、最大剪应力变化进行了计算分析。结果表明,四川地区地壳内的局部最大主压应力变化和最大剪应力变化区域与同期发生地震活动的区域具有较好的一致性。
Based on Green's second interior integrotion, the formulas to colculate interior stress variation from displacement velocity on earth surface is derived in this paper. The computed methods are discussed and analyzed. In the last, the maximum principal stress and shear in depth 15 km of the earth crust is computed by using GPS displacement velocity data observed from 2001 to 2005,2004 to 2007 in Sichuan region. The results show that both maximum compressional principal stress variation and shear locate in the area where moderate strong earthquake Ms=6.0 or larger than 6.0 occurred during the GPS observation.