通过对汶川地震后震区附近的GPS连续站资料的高精度数据处理,获得各测站的时间序列。利用时间序列分析,求得震后松弛时间约为38d,并获得各测站的震后位移。基于粘弹性松弛模型,对震后位移进行了模拟,反演出龙门山地区地壳的弹性层厚度的最佳估值为45km,粘弹性层的粘滞系数的最佳估值为1.8×10^19Pa·S,该结果与地震学以及地球物理学等给出的结果基本一致。
By high precision data processing, we obtain the coordinate time series of GPS con- tinuous observation stations, which were located in the seismic area along the Longmen Shan Fault after the 2008 Wenchuan earthquake. Through the time series analysis, the postseismic relaxation time is 38 d, and postseismic displacements of these stations are obtained simultaneously. Based on the viscoelastic relaxation model, the thickness of the elastic layer and the coefficient of viscosity of the viscoelastic layer in Longmen Shan area, are inverted by simulating the observed postseismic displacements. The preferred values of the thickness of the elastic layer and the coefficient of viscosity of the viscoelastic layer are 45 km and 1.8× 10^19 Pa · s separately, which are in general accord with the results obtained by seismological and geophysical methods.