Hydrogeological precursors of earthquakes and volcanic activations according to observation data in Kamchatka Peninsula wells

Abstract

The purpose of the study is generalization of data on the manifestations of hydrogeological earthquake precursors and volcanic activations based on long-term observations in the wells of the eastern part of the Kamchatka Peninsula. The main problem under consideration is the connection between the manifestations of hydrogeological precursors in several wells with the values of the magnitude Mw and epicentral distance of earthquakes to the wells de as well as with the parameters of seismic action in the observation area including specific density of seismic wave energy e and macroseismic intensity of shaking IMSK-64. The study results revealed that hydrogeological precursors in two-four wells had been manifesting for the period from 1 to 9 months before the strongest earthquakes with Mw = 6.6–7.8 at the epicentral distances de = 90–300 km. Such earthquakes were accompanied by the shakings of the intensity of IMSK-64 = 4–6 points. The specific density of seismic energy under such earthquakes was minimum 0.1 J/m3. The hydrogeological precursors were confined to the area for which the ratios of the earthquake epicentral distance de to the maximum linear size of the earthquake source L, km ranged from 1 to 3.7. Using the established relationships between the manifestations of hydrogeological precursors and earthquake parameters, weekly prognostic conclusions were made for expert earthquake prediction councils based on the data of current observations in wells. The well located at the distance of 15 and 20 km from the Koryaksky and Avacha active volcanoes featured the anomalous rise of groundwater pressure before the eruptions in 1991 and 2008– 2009. Therefore, a conclusion can be drawn that observation equipment operating in wells, the study results of hydrogeological precursors of earthquakes and volcanic eruptions as well as their application experience in the work of expert councils can form the scientific and technical basis for the development of geoinformation prediction technology for natural disasters in the Kamchatka Krai.