Magnetotelluric monitoring of geodynamic processes

Abstract

Electromagnetic (EM) monitoring of geodynamic processes can be based on the two different seismo-electrical phenomena: a change in resistivity of some geological cross-sections and a generation of EM fields of internal (geodynamic) origin. Continuous observation of the natural magnetotelluric (MT) field simultaneously provides information on both such phenomena. The transfer functions between components of the MT field reflect geoelectrical section and the residual field includes the EM field of internal origin. Their variations in time give independent information on geodynamic processes. The transfer functions and the residual field can be determined by known deterministic methods, although it appears more convenient to apply the methods of adaptive data processing. They elicit information on both phenomena in real time. Continuous MT observations were carried out at the Bishkek geodynamic testing ground (Kirgizia) during 1993. Their results show how informative MT monitoring is.