Overview of modern hardware and software for near surface electromagnetic sounding in the frequency domain

For the study of the first ten meters of the ground, instruments operating in the frequency domain are most widely used. The compactness, speed of operation, ease of operation of such equipment, as well as the quality of the information obtained, determine its applicability for solving a wide range of issues: from searching for local objects to identifying structural features of the upper part of the section. The article provides an overview of current hardware and software developments for near surface electromagnetic soundings in the frequency domain. A description of all types of non-contact equipment from major world manufacturers is given. The features of both the hardware itself and the approaches to their implementation are described. Methods of primary processing and data inversion are considered. Conclusions are drawn about the need to find new ways to eliminate of equipment deficiencies.

Electromagnetic research in the Altai-Sayan mountain region

A new software-measuring complex has been developed for recording non-stationary electromagnetic soundings based on mobile modules created on the basis of 24-bit ADCs, with built-in GPS receivers, with recorders located directly at the field sensors, arithmetic sampling step and recording of all signal realizations. The deep structure of the Uimon depression in Gorny Altai has been studied based on the time-domain electromagnetic sounding. Research is relevant due to the high seismic hazard of the area, and is also in demand for prospecting and exploration of predicted minerals here. To construct geoelectric models, data from several years of measurements were used, during which more than 60 soundings were performed. At this stage, the interpretation was performed using computer systems within the framework of a horizontally layered model. The interpretation results are presented in the form of sections and threedimensional visualizations, which clearly reflect the structure of the depression. Further, three-dimensional modeling and additional measurements are planned to verify and refine the results obtained.

Mathematical simulation of pulsed electromagnetic soundings with a spatially distributed system of deviated wells

We have developed a mathematical model describing the sounding process with a pulsed electromagnetic field source in a 3D region complex in physical parameters and geometric structure. For its time discretization, the time Fourier transform is used. Through the vector finite element method, we have obtained a discrete analogue in spatial coordinates of the original problem. The simulation examples are provided.