Abstract: Based on the data conducted from 18 MT sites in west Yunnan, the deep conductivity characterics along the longitudial and transverse directions of the geological structure are studied, The results indicate that the deep eletrical structure in this area is a multiple-layer structure with 4-5 electrical layers. There is great lateral inhomogeneity in the deep eletrical structure which are apparently controlled by the regional geological structure. There exists a widespread highly conductive layer in the crust, and two upper mantle highly conductive layer uplift zones are found, one is situated in Jianchuan-Heqing with the principal axis of NNW direction and another in Tengchong-luxi with approximately NS direction.The relationship between the electrical structure of the crust and upper mantle and the geotectonics, the formation of northwest Yunnan rift basin and the relationship between seismic activity and the deep geological structure are also discussed in this paper.

Key words: West Yunnan, Apparent resistivity, The crust and upper mantle, Conductive layer, Tectonics activity, Seismic

摘要： 本文根据滇西地区18个大地电磁测深点资料的数据处理和分析结果,对测区深部导电率在纵、横向上的变化特征进行了研究。结果表明:滇西地区深部电性为多层结构,大致可分四至五个电性结构层;深部电性结构横向变化大,明显受区域构造控制;该区上部地壳内普遍存在低阻层;上地幔高导层明显存在两个隆起区,一个以剑川—鹤庆为中心呈北北西向展布的隆起区,另一个以腾冲—潞西为轴呈南北向展布的隆起区。 本文还讨论了地壳上地幔电性结构与大地构造的关系,滇西北裂陷区盆地的形成,以及该区地震活动与深部构造的关系。

关键词: 滇西, 视电阻率, 地壳上地幔, 高导层, 构造活动, 地震