RESULTS OF SHORT-TERM MONITORING OF HELIUM CONTENT AND GENERALIZED INDICATORS IN THE UNDERGROUND WATERS OF THE ALTAI MOUNTAINS

Abstract

The relevance of the work is caused by the need to improve the methods for monitoring the characteristics of groundwater and their changes in the seismically active regions of the Altai Republic. Groundwater is an indicator of seismic processes and they react to changes in the stress-strain state of rocks in the zones of foci of upcoming tectonic earthquakes. The aim of the work is to identify short-term changes in the helium content and generalized hydrogeochemical indicators in the previously identified highly dynamic groundwater monitoring facilities of the Altai Republic in relation to the search for precursors of strong seismic events. Research methods. The work is based on the results of daily monitoring of groundwater in the Altai Republic, which was carried out in January–March 2021 at two observation points for temperature conditions and the qualitative composition of groundwater – well and a column – f the Territorial Center «Altaigeomonitoring». Results. The purpose of the work is to study the change in helium content in groundwater and its hydrogeochemical characteristics at several points of the geological environment monitoring in order to search for precursors of strong seismic events. For this study, we used two groundwater observation points located in Gorno-Altaisk (street water fountain) and in the village Stariy Beltir (borehole) distant from each other of more than 200 km. These monitoring points were chosen due to the fact that a significant change in the characteristics of groundwater was recorded there during the preparation and course of seismic events in the region. The work gives a characteristic of the seismic setting of the Altai-Sayan region during the monitoring period. In order to identify the dynamics of helium content and hydrogeochemical characteristics of groundwater, we started studying these characteristics in the period of January 14 – March 22, 2021. It is shown that the Stariy Beltir monitoring point, located in the fault zone near the epicentral zone of the Chuya earthquake (2003), is characterized by a high sensitivity of changes not only in the hydrogeochemical characteristics of groundwater, but also by a high response of helium content dynamics to earthquakes. It was revealed that the Mongolian earthquake (2021) did not affect the hydrogeochemical composition of the studied monitoring points located on the territory of Gorny Altai, at the same time, the seismic events closest to them are reflected in the presented groundwater monitoring points. The chosen monitoring points in some cases do not overlap each other and react mainly to the nearest earthquakes, including weak ones. The most dynamic response to earthquakes was noted in helium, pH, Eh, and temperature.

Keywords

• groundwater
• groundwater monitoring
• hydrogeochemical characteristics
• helium
• rupture zones
• earthquakes