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

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.