甘宁青地区强震孕育的深部电性和力学环境

THE DEEP ELECTRICAL AND MECHANICAL ENVIRONMENT OF STRONG EARTHQUAKE PREPARATION IN GANSU, NINGXIA AND QINGHAI REGIONS

以 2 0 0多点次的大地电磁测深资料和 6条人工地震测深剖面的资料为根据 ,结合重力测量和地热流观测资料 ,分析研究了甘肃、宁夏和青海地区的强震孕育的深部环境 .认为强震孕育在增厚的低阻层的顶部 ,低速层的上方以及介质在横向上电性和力学性质均剧烈变化的环境之中 .这些条件的实质是在地应力作用下纵、横向地层变形不一致 。

The deep environment of strong earthquake preparation in the region of Gansu,Ningxia and Qinghai is analyzed and discussed based on more than two hundred MT measurement data and six artificial seismic sounding profiles, combined with gravitational and geothermal fluid observation data.It is suggested that strong earthquakes often develop and prepare in the top of thick lower resistivity layer,above the lower velocity layer and in the media with dramatic lateral variation electrically and mechanically. The nature of these conditions implies that under the affects of stress,the easiest place for stress concentration is the place where vertical and horizontal deformations of crust layers are inconsistent.