深部电性变化前兆大地电磁测深法的可分辨性  

THE RESOLUTION OF THE MAGNETOTELLURIC SOUNDING FOR THE PRECURSOR OF DEEP ELECTRICAL VARIATION

作　　者：林长佑[1] 刘晓玲[1] 武玉霞[1] 

机构地区：[1]国家地震局兰州地震研究所

出　　处：《华北地震科学》1990年第1期61-68,共8页North China Earthquake Sciences

基　　金：地震科学联合基金项目

摘　　要：本文分析了地表各处起因于深部电性变化前兆的大地电磁响应函数的变化形态、特征,探讨了对此大地电磁测深法的可分辨性的某些问题。研究表明,在离震中稍远的震源外围区,由扩展膨胀各向异性所引起的深部电性变化引起了某些大地电磁响应函数明显的可分辨的变化;发展中的地震断裂带和震前断裂蠕滑段,作为一个两维导电沟,可以引起邻近区域视电阻率,阻抗相位、维系数的可分辨的变化;对于一个异常的震源导电体,地表大地电磁响应函数显示出了两维模拟异常的某些类同和差异。In this paper the variation pattern and the character of the magnetotelluric (MT) response functions at various positions on the earth surface, which are due to the deep electrical variation, are analysed, some problems of the resolution of MT sounding for them are discussed priliminarily. It is indicated that in regions around focus, farther from the epicentre, the deep electrical variation, due to the extensive-dilatancy anisotropy (EDA), leads to the distinguishable variations of MT response functions; the earthquake fault during the development and the creep portion of fault before earthquake, as a conductive dike, can lead to distinguishable variations of the apparent resistivity phase of impedance, dimensional coefficients in its nearby region; for an anamalous conductive focal volume, the MT response functions at earth surface appear to be either some analogous to or different from the results of two-dimensional models.

关 键 词：电性 大地电磁测深 可分辨性 

分 类 号：P315.7[天文地球—地震学]