An analysis of hydrogeological behavior in the Geyser Valley, Kronotskii nature reserve, Kamchatka after the disaster of June 3, 2007

Abstract

This paper describes the results from observations of the hydrogeological behavior in the Geyser Valley in 2007–2013 at the main monitored geysers and springs and in Lake Podprudnoe after the disastrous landslide of June 3, 2007. According to observations at Bolshoy Geyser, its mean eruption period is almost two times shorter compared to that before the landslide; it is 63 min now. Its activity is controlled by the level of Lake Podprudnoe. Velikan Geyser was found to have a significantly shorter period of eruption, decreasing from the mean annual value of 379 min (in 2007) to 335 min during the first 3 years after the disastrous landslide, with the mean annual eruption period subsequently stabilizing. It was found that Velikan Geyser showed an increasing period of eruption within its hydrogeologic cycle during winter (by about 50 min on average). The mean annual value of the deeper discharge component in the hydrothermal system (as determined by the chloride technique) is estimated as 215 kg/s; it was observed to decrease (by 30%) during the spring-summer flooding. The injection of meteoric waters from Lake Podprudnoe did not produce any significant hydrochemical changes in the Velikan and Pervenets geysers, but the main component of the deeper heat carrier was found to be diluted in Bolshoy Geyser. On the whole, the gas composition of the pipes in the geysers and boiling springs is dominated by the atmospheric component, while the feeder reservoir of Velikan Geyser is dominated by CO2 and N2 with considerable concentrations of methane and hydrogen. TOUGH2 modeling showed that the decrease in the eruption period was related to the hydrodynamic effects of Lake Podprudnoe. We examined the influence of seismicity on the eruption behavior of Velikan Geyser.