摘要
本文用川滇及其邻区震源深度分布的规律、震源机制P轴出地点的资料、及现有水压致裂应力测量结果,讨论了印度板块缅甸弧的俯冲深度、形状及地壳隆起的力学机制。指出缅甸弧沿北东方向向川滇地块俯冲的角度为19.1°—26.6°;挤压作用可能不是我国西南地区大规模隆起的唯一原因。由于我国川滇地区的地形、地貌和地质构造格局都受到印度板块俯冲作用的影响和控制,因此它们的地震活动性有着密切的联系。从1900年至1980年期间,缅甸弧附近和川滇地区的地震活动都可分为四个活动期,川滇地区的地震活动期的开始与结束都较缅甸弧附近地区相应的地震活动期滞后,滞后时间分别为2年和3年。
The underthrust depth and shape of the Burma Arc of the India Plate and the mechanism of crustal uplift were discussed with the regular pattern of focal depth distribution and the information of points where P axis of seismic mechanism comes up and the results of stresses measured with hy-drofracturing technique from Sichuan and Yunnan provinces and the neighbour regions in this paper. It is shown that the underthust angle where the Burma Arc along NE direction underthrusts into the Massif Sichuan-Yunnan is 19. 1°——26. 6°. The compression may be not only the cause of crustal lift ona large scale in SW region of China. Because the topography, landforms and geological structure frame are controlled and influenced by the action of the India plate underthrusting into Massif Chuan - Dian, the seismic activities between the Burma Arc and Massif Sichuan-Yunnan are closely relative. From 1900 to 1980, the seismic activities of the Burma Arc and Massif Sichuan-Yunnan can be divided respectively into 4 active periods, the beginning and end of every active period in Sichuan-Yunnan region are respectively late than these of the Burma Arc, the delayed time is respectively 2 and 3 years.
出处
《中国地震》
CSCD
北大核心
1992年第1期68-75,共8页
Earthquake Research in China
