Geophysical surveys in the area of the Krylatovskaya water well

Abstract

Relevance and purpose of the work. Surface sources of clean water are increasingly depleted. In this regard, the role of underground sources of drinking and domestic water supply is increasing. Geophysical exploration methods can be an e ective tool for fnding groundwater. The tasks of the research included determining the possibilities of magnetic prospecting in the areal search for promising zones, and identifying the features of electromagnetic fields during audiomagnetotelluric and magnetovariational soundings in the area of an operating water well. Methodology. The magnetic field was surveyed with an MMP-203 proton magnetometer (Geologorazvedka plant, Leningrad). Electrical exploration included vertical electrical sounding (VES) with ERA equipment (GNPP Geologorazvedka, St. Petersburg) and recording of audio magnetotelluric fields with OMAR-2 equipment (IGF UB RAS, Ekaterinburg). Results. The result of the magnetic survey was a map of the anomalous magnetic field of the study area, where the water-abundant groundwater zone of the weathering crust can be distinguished by structural features. The zones of tectonic faults, promising for the presence of fractured-vein waters, are confedently distinguished by positive linear anomalies of the magnetic field. The characteristic features of electromagnetic fields during audiomagnetotelluric and magnetovariational soundings in the area of distribution of fractured waters have been clarified. The most revealing behavior is the behavior of the real and imaginary quadratures of the magnetovariational tipper, characterized by minimum values and zero crossing, respectively. According to the results of electromagnetic sounding, an increase in the thickness of the weathering crust with a decrease in resistance is recorded in the area of the water intake well, which is evidence of its water cut. Conclusions. The significance of magnetic prospecting for clarifying the structural and geological structure of the territory when searching for water-saturated zones has been determined. The high e£ciency of electromagnetic soundings on direct and alternating current was confirmed to determine the nature, depth and power of the identiŽed structures. Traditionally studied, in the search and exploration of groundwater, geophysical felds are replenished with new electromagnetic parameters. These include the module and quadratures of the audio range magnetovariational tipper. The research results indicate that these parameters are anomalous in relation to aquifers, which allows us to give reasonable recommendations on the location of drilling production wells.