Mapping of the Fault Zones on Basis of Geomagnetic Variations Due to Seismic Wave Propagation

Abstract

tectonic faults differ from the properties of surround rock. The fault properties determine behavior of the fault due to different external influences. Seismic waves propagating through the fault result to local magnetic field variations. Amplitude and intensity of these variations depend on the conditions for transformation energy between mechanical oscillations and magnetic field. Registrations of the seismo-magnetic effect at the Earth’s crust surface allow determining the presence of the fault and estimating its internal properties. We carried out synchronous registration of seismic waves and magnetic variations along the profile crossing the fault zone situated at the central area of the Russian platform. Geomagnetic variations caused by seismic signals resulting from open-cast mine blasts were analyzed. As a result we determined that magnitude of seismo-magnetic effects is maximum in the central fault's zone and decreases appreciably according to exponential law as the distance from the fault increases. It shows that the transformation of mechanical energy of vibrations into the energy of geomagnetic variations occurs more intensively in the fault. It allows determining the fault location firstly and estimating its broken state and present-day activity secondly.