Abstract <p>The results of experimental studies on monitoring variations in apparent resistivity, as a precursor to earthquakes, based on audiomagnetotelluric soundings at the Goryachinsk test site (Baikal region) are considered. Different types of groundings of receiving electrical lines (brass, lead, chlorine–lead electrodes) have been compared. Chlorine–lead electrodes are characterized by the most stable data. In selecting stress–strain sensitive zones for the installation of monitoring equipment, the geological features of the territory were analyzed, field experimental studies were carried out to study preselected sites at fault zones, and test monitoring sessions were conducted to assess the response to tidal deformations of the Earth. The test monitoring data were used to select the frequency range for monitoring variations in apparent resistivity. The obtained apparent resistivity curves are characterized by stable behavior and small spread of values in the frequency range of 7–300 Hz. Therefore, it is advisable to perform standard magnetotelluric processing of monitoring data to obtain the apparent resistivity and impedance phase curves in the specified frequency range, and analyze variations in the magnetic and electrotelluric fields at frequencies below 7 Hz. According to the test monitoring results, it was found that tidal effects are observed in the apparent resistivity values for the E-polarized field. For the H-polarized field, there are no significant fluctuations. The values of variations with respect to the average level of 35–36 Ω m are small, 0.3–0.4 Ω m (about 1%). The results of apparent resistivity monitoring demonstrated high measurement accuracy, about 0.3%. The selected stress–strain sensitive zone can be used for long-term monitoring.</p>