CORRECTION OF THE ELECTROMAGNETIC MONITORING DATA FOR TIDAL VARIATIONS OF APPARENT RESISTIVITY

Abstract

The use of the ELF (extremely low frequency) radio station “Zevs” for the study of the stress–strain state of geological media is considered. Analysis of prior research on the connection between tidal phenomena and apparent resistivity ρa variations at earthquake prediction sites are made. In the ELF range experimental measurements of artificial electromagnetic field impedance and the results of calculation of tidal deformations are considered. A high degree of correlation of ρa values and vertical deformations of the Earth surface ΔH are noted. Diurnal ρa changes of 7% due to tidal phenomena, were recorded with measurements accuracy of ±0.6%. To increase the reliability of earthquake prediction it is necessary to correct the electromagnetic monitoring data for tidal effects using correlation equations between ρa and ΔH.