基于GPS形变资料的川滇地区应力场数值模拟研究

基于近10 a的GPS坐标时间序列获得川滇地区速度场，结合地质资料将该区划分为7个块体，并使用ABAQUS建立三维有限元模型，提取速度场边界值作为模型约束条件，模拟得到应力场。位移场数值模拟结果显示，模型较好地反映了川滇地区西北部青藏高原推挤、东侧扬子块体阻挡的格局，同时位移方向在菱形块体及拉萨块体内部绕东构造结顺时针旋转，与实际相符。应力场模拟结果表明，龙门山断裂带、鲜水河断裂带和安宁河断裂带交界区域南北两侧、小金河-丽江断裂带西段与澜沧江断裂带交界处南北侧、南汀河断裂带西段南北侧、红河断裂带中段东西侧均存在明显的应力分布不均现象，地震危险性较大。

Numerical Simulation of the Stress Field in Sichuan-Yunnan Region with GPS Deformation Data

Based on GPS coordinate time series from this decade, the velocity field of the Sichuan-Yunnan region is obtained. According to geological data, we divide this region into 7 blocks, then find the three-dimensional finite element model by ABAQUS. Through extracting the boundary value of the velocity field as model constraint conditions, we obtain numerical simulation results of displacement and stress field. The results show that our model clearly reflects the situation of pushing forces from Qinghai-Tibet plateau in the northwest and prevention from Yangzi block in the east. The displacement direction rotates clockwise on eastern Himalayan syntaxis inside rhombic block and Lhasa block. These results conform with reality. Simulation results of stress field indicate that the stress distribution is obviously uneven in some areas, such as the border region of Longmanshan, Xianshuihe and Anninghe fault zone, the border region of Xiaojinhe-Lijiang and Lancangjiang fault zone, the south and north flanks of Nantinghe fault zone, as well as the east and west flanks of Red River fault zone. Seismic risk in these areas is larger than other regions.