Горячинская активизация Ямбуйской зоны транстенсии в 2013–2015 гг.: Косейсмическая химическая гидрогеодинамика подземных вод на ЮВ побережье Среднего Байкала

Abstract

Variations of Si, Na, Li, 234U activity, and 234U/238U activity ratio in thermal and cold groundwaters, as well as cooled hydrotherms from active faults in the SE coastal area of Middle Baikal are considered. For the Maksimikha area, hydrogeochemical monitoring data of 2013–2015 with interpretation in terms of chemical hydrogeodynamics: temperature, depth of water reservoir and opening–closing of microcracks for circulating water. When comparing series of hydrogeochemical monitoring with a series of earthquakes K = 10.5–12.7 of the Goryachinsk seismic reactivation in Middle Baikal, an increased sensitivity of responses to earthquakes at the station of cooled hydrotherms from the transition zone of the lower hydrogeodynamic floor is revealed in comparison with the responses of fracture-derived cold water from the upper floor. The Maksimikha groundwater reservoir is considered as a representative reservoir located along the in the Yambuy transtension zone that is lateral structure of the South Baikal basin. Coseismic hydrogeodynamics of the Maksimikha reservoir in 2013–2015 is referred to the time interval preceding the landmark Goloustnoye earthquake on September 05, 2015, which corresponded to the conditions of maximum compression of the crust of the Kultuk reservoir, localized at the main structural line of the Baikal Rift System, in the 2008–2020 seismogeodynamic cycle.