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为了研究芦山地震的孕震过程和震源区的长期构造过程以及解释实测的震后形变和重力资料,采用分层介质模型,利用数值模拟的方法,考虑区域流变系数,计算了地震引起的地表同震、震后的形变和重力变化以及区域内部分GPS与重力连续观测台站的震后形变和重力变化的时间序列.结果表明:芦山地震的地表同震形变显示出发震断层明显的逆冲特性;粘弹性松弛效应引起的震后地表形变和重力变化比同震形变和重力变化的范围明显扩大,但随着粘滞系数的增加,变化量明显减小;观测台站的震后变化时变曲线显示震后形变和重力变化在震后50a间变化显著,100a后基本平缓,趋于稳定;模拟计算的GPS台站中除了MEIG台和MYAN台以外,其余台站的震后观测必须考虑粘弹性松弛的影响.
In order to study the seismogenic process of the Lushan earthquake and the long-term tectonic process of the source area and to explain the measured post-earthquake deformation and gravity data, the stratified medium model, the numerical simulation method and the regional rheological coefficient were used to calculate the surface Coseismic and post-earthquake deformation and gravitational changes, as well as time series of post-earthquake deformation and gravitational changes of GPS and gravitational continuous observational stations in the region.The results show that the surface coseismic deformation of Lushan Earthquake shows obvious overturning Characteristics; viscoelastic relaxation caused by post-earthquake surface deformation and gravity changes than the coseismic deformation and gravity range of a significant increase, but with the increase of the viscosity coefficient, the amount of change is significantly reduced; observation station changes after the earthquake The curves show that the post-earthquake deformation and gravity changes significantly after 50 days of earthquake, and are basically flat after 100 years and tend to be stable. In addition to the MEIG and MYAN stations in the simulated GPS stations, post-earthquake observation of the remaining stations must be considered The effect of viscoelastic relaxation.