Reflection of Strong 2020–2021 Baikal Rift Earthquakes in the Earth's Magnetotelluric Field Observation Data.

Abstract—In this paper, we explore the findings of monitoring the components of the Earth's natural electromagnetic (EM) field obtained in 2020–2021, as well as their link with rather strong seismic events within Baikal Rift Zone (in particular, the Kudarin earthquake (Dec. 9, 2020, M_w = 5.5)). During the observations of the magnetotelluric field more than one month prior to the seismic event, the increased conductivity of the tensor-sensitive parts of the sounded soil was recorded due to the displaced release of conducting fluid to the weak crust zones before the earthquake. 24 hours before the seismic event, the anomalous behavior of the electrical field vertical component (E_z) was observed as U-shaped oscillations every 5-30 s due to the electrical charge excitation and relaxation from the compression of quartz-containing rock. The first approximation showed that the analysis of magnetotelluric (MT) monitoring data could help identify medium- and short-term precursors of seismic events. [ABSTRACT FROM AUTHOR]