Coseismic variations of Li in groundwaters from station 27 of the Kultuk polygon

Abstract

Monitoring results of the thermophilic trace element element Li and related macrocomponents Cl and S in groundwaters from station 27 in the Kultuk polygon. The dependence of their variations on earthquakes and aftershocks of the 2020–2022 Baikal-Khubsugul reactivation is established. From Na/Li geothermometry, 234U/238U activity ratio, and 234U activity, groundwater sources in a deep reservoir with a temperature as high as 100 °C or more under crust stretching and those with a temperature as low as 8 °C under crust compression are designated. Phases of stabilization, increase and decrease in groundwater temperature are deciphered in the course of the development of a complete seismogeodynamic cycle of compression and extension of the crust.