【摘要】 自1990年以来我国西部及邻近地区先后发生了6次7.0级以上地震,这些地震的震中位于35°N线附近,其纬度界于34.4°~36.2°N之间,平均纬度为35.45°N。美国哈佛大学给出的震源机制表明,这些地震的主压应力轴方位一致性较好,都为NE向,似乎说明这些地震的发生是在统一的应力场作用下的结果,可能与印度板块对我国大陆的推挤作用有关。结合地质构造和余震分布确定了发震断层,计算了它们产生的应力场,根据库仑破裂应力变化,分析了它们之间的相互影响。结果显示,在这些地震中,对后续发生的地震可能具有促震作用。根据引潮力在震源断层面上产生的有效剪切应力,分析了引潮力对这些地震的触发效应,结果没有显示这些地震的发生受到明显的引潮力触发。更多还原

【Abstract】 There are 6 M>7.0 earthquakes successively occurred in the west of China and nearby regions since 1900.They are located near the 35°N line,and their latitudes range between 34.4°~36.2°N with the average of 35.45°N.According to focal mechanisms given by Harvard University,the azimuths of these earthquake’s compression stress axes are almost along the direction of northeast.This paper shows that these earthquake′s occurrences could result from the unified stress field possibly related to the push of the Indian plate to mainland China.We determined their seismic source faults by tectonic fault and the special distribution of the aftershocks,and calculated the stress fields caused by the earthquakes.According to the change of the Coulomb failure stress,we analyzed the interactions of them.The result shows that these s,the former earthquake have triggering effects on subsequent earthquake.According to the effective shear stress on the focal fault plane caused by the earth tide,the triggering effect of the earth tide for these earthquakes is analyzed,the result does not demonstrate that these earthquakes are triggered by earth tide.更多还原