关键词: 中国西北地区, 大地电磁测深, 地壳, 上地幔, 电阻层, 地震

Abstract: Based on the observation data from 52 MT stations, this paper deals with the change of lateral electric property in crust-upper mantle in partial region of Northwest China. According to the depth of upper interface of the first low resistivity layer in upper mantle, the interesting region can be devided to four kinds of areas: shallow(depth of 55-90km), medium-shallow(90-110km), medium-deep(110-160km) and deep(160-250km).The electric property at depth associated with 6 great earthquake cases is discussed also. The results indicate that the area with steep gradient zone of the top of upper mantle, the area with evident change of lateral electric property in crust, and the area with particularly thickened low resistivity layer in crust may be considered as potential earthquake areas.

Key words: Northwest China, Megnetotelluric sounding, Crust, Upper mantle, Resistivity layer, Earthquake