基于GPS观测的昆仑山8．1级地震微动态变形研究

ON MICRO-DYNAMIC DEFORMATION INFORMATIONS OBTAINED FROM GPS OBSERVATIONS DURING KUNLUN MOUNTAIN Ms 8.1 EARTHQUAKE IN 2001

借助板内块体的刚性运动、应变综合模型,利用青藏块体东北缘地区的GPS基准站连续观测数据,通过计算各测站累计差分位移得出该区域变形参数动态变化。结果表明,2001年昆仑山8.1级地震前后变形参数时间序列存在一致的变化趋势,同震变化明显的参量有东西向应变、最小主应变、面膨胀率与第二剪应变。该综合模型可以解释昆仑8.1级地震引起区域应变释放、调整的机制。研究还认为利用区域变形参数组合有可能识别出大震临震异常。

By means of the synthetic model for rigid movement and strain of the intro-plate blocks, and through computing the accumulated difference displacements derived from the observation fiducial GPS stations in the north- eastern edge of Qinghai-Tibet block, the dynamic variations of the continuous deformation parameters in this area are obtained. The results show that there was coherent vary tendency between these parameters before and after the KunLun Mountains Ms 8.1 earthquake, it is discovered that the four time series, the east-westward strain, the least principal strain, the superficial expansion rate and the second shear strain are significant. The mechanism of strain releasing and adjustment induced by the earthquake in the area can be interprated with this Model. It is possible to identity imminent anomalies of a large earthquakes in the region by assembling deformation parameters.