摘要
采用各向同性弹性地球模型推导了地面位移场速率与地壳内任意点应力场变化的边界积分关系,同时利用青藏高原东北缘1999～2001年观测的GPS资料对观测区地壳深度为5km和25km的主应力和最大剪应力进行了计算分析。结果表明,青藏高原东北缘的主应力变化主要集中在祁连山断裂、海原断裂等,在1920～1954年间历史上发生过多次震级为7.0～8.5级强震的断裂附近,并具有主应力变化沿断层走向分布、最大剪应力沿断层走向交替变化等特征。
The formula based on the boundary integral equation to computed the variation of both the main stress and maximum shear variation in the depth of 5, 25 kilometers of the earth crust in northeastern margin of Qinghai-Tibet Plateau is calculated and analyzed by using two times Global Positioning System (GPS) measurement data which were observed in 1999 and 2001 respectively. The computed stress variation manifests that the largest main stress variation focus on the Qilianshan and Haiyuan faults and the maximum shear variation went along the Qilianshan fault alternatively where many strong earthquakes larger than Ms7.0 had occurred between 1920 and 1954.
基金
国家自然科学基金资助项目(49774214)
关键词
GPS观测
应力场变化
强震
青藏高原
GPS measurement
stress variation
strong earthquakes
Qinghai-tibetan
