川滇菱形块体东边界地壳形变研究

ANALYSIS OF CRUSTAL DEFORMATION IN EAST BOUNDARY OF SICHUAN-YUNNAN BLOCK

根据地质资料和GPS资料,在断层分布密集的地区用模拟断层的位错替代多断层位错,建立了川滇菱形块体东边界的非震位错模型.利用GPS区域网资料,采用改进的蒙特卡罗法和遗传算法,联合反演了川滇菱形块体东边界的活动特性,得到如下认识:1)小江断裂是高应变积累闭锁区,鲜水河断裂次之,安宁河和则木河断裂应变积累程度最低.2)2001～2004年与1999～2001年相比,鲜水河北西段应变积累即锁定程度没有明显变化,南东段略有加强;安宁河略微减弱;则木河没有明显的变化;小江断裂各段的锁定程度均有显著的增强.3)各断裂的运动特点在空间上呈现出分段性.4)边界带的变形主要集中在川滇菱形块体一侧.

On the basis of geological and GPS data, we proposed an aseismic negative dislocation model of east boundary of Sichuan-Yunnan block, which uses the dislocation of a simulated fault to replace the dislocation of multi-fault. In the same time, we jointly inversed dynamic characteristics of the easterm boundary of Sichuan-Yunnan block by modified Monte Carlo algorithms and genetic algorithm with GPS data of local network and the following results had been obtained.①The Xiaojiang fault is locked zone of strong strain accumulation, Xianshuihe fault is weaker,Anninghe fault and Zemuhe fault belong to unlocked zones. QIn strain accumulation,as compared with in 1999-2001, in 2001-2004, the Xiaojiang fault appears strongest, southeast segment of Xianshuihe fault a little stronger, and Anninghe fault weaker, northwest segment of Xianshuihe fault and Zemuhe fault unvaried. ③The dynamic characteristic of the faults appear segmented in space.④The deformation of the boundary area concentrates mainly within Sichuan-Yunnan block,i, e. on the western side.