断层几何障碍与地震的发生和发展——以剑川-洱源伸展带为例

本文应用几何障碍的概念,对剑川-洱源伸展构造带的几何结构、1982年至1986年沿构造带的地震活动及其相互之间的关系进行了分析研究和数值模拟,结果表明:现代构造带的几何障碍是可能的潜在震源区;构造几何结构、障碍的规模、应变能积累三者之间有着一一对应的关系;障碍点之间存在相互作用,它们具有导致地震破裂发生和阻碍破裂发展的双重属性,从而控制着地震的孕育和迁移

GEOMETRIC BARRIER OF FAULTS AND RUPTURING PROCESS OF EARTHQUAKES: EXAMPLE FROM JIANCHUAN-ERYUAN EXTENSIONAL ZONE

The neotectonics and seismicity in Jianchuan-Eryuuan area, northwestern Yunnan exhibit a model of the geometric barriers of the faults relative to the earthquake rupturings.Field investigations have revealed that the modern Jianchan-Eryuan extensional zone is made up of two longitudinal zigzag rupture belts which experienced two important stages of development in the past: pulling-apart within the overlapping area of NE-trending strike-slip faults in early Quaternary, and zigzag extension in late QuaternaryEarthquake data from 1982 to 1986 show that five earthquake events occurred along the extensional belts corresponding with the trend of the zigzag ruptures. First event happened in July, 1982 at the northern end of the zone, and then the following seismic swarms occurred one by one towards the south, each of which was located at the geometric barrier of the faults constructed by the intersections of faults with different behaviors.In order to describe the mechanism of the seismicity