Korobeinikov A. G., Ismagilov V. S., Kopytenko Yu.A., Petrishchev M. S. Processing of experimental studies of the Earth crust geoelectric structure based on the analysis of the phase velocities of extra-low-frequency geomagnetic variations

Abstract: the article presents the results of experimental study of geoelectric structure of the Earth crust held in Karelia. Simultaneous measurements of extra-low-frequency variations of the Earth electromagnetic field were held in August 2012 near Tolvuya village (Karelia) to determine the depth of crustal conductivity anomalies. The choice of this exact place was made due to the fact that in this area there are outputs of highly conductive shungite rocs on the Earth” surface. For the research five highly sensitive trinary geomagnetic-variation systems GI–MTS-1 where placed at a distance of 10.5 km from each other. The data was recorder at a frequency of 50 Hz. At all five systems the data processing was performed in two ways using magnetotelluric method (DOLE) and phase-gradient sensing to analyze the changes in apparent resistivity with increase of the depth. The phasegradient sensing method was developer in the St. Petersburg branch of the N. V. Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Sciences and it requires at least three geomagnetic-variation systems placed in a triangle on the earth’s surface. Comparison of the interpretation results of the magnetotelluric method and method of phase-gradient sensing showed their good match.

Keywords: