On the relationships of water-level variations in the E-1 well, Kamchatka to the 2008–2009 resumption of activity on Koryakskii volcano and to large (M ≥ 5) earthquakes

Abstract

We discuss the water-level variations in the E-1 well for the time period between May 2006 and 2010, inclusive. A trend towards an increasing level at an abnormally high rate occurred from mid-2006 to December 2009. This increase is regarded as the response of the aquifer of gas-saturated ground water that exists in the volcanogenic-sedimentary deposits of the Avacha volcano-tectonic depression to volumetric compression strain changes during the precursory period and the occurrence of a swarm of small earthquakes \(\left( {K_{S_{\max } } = 8.3} \right)\) in the area of Koryakskii Volcano and to its phreatic eruption. We estimated the volumetric compression as Δɛ = −(4.1 × 10−6−1.5 × 10−5) from the amplitude of water-level rise using the elastic parameters of the water-saturated rocks. While the strain source was active, we observed a decreasing sensitivity of the hydrodynamic regime in the well to the precursory processes before large (M ≥ 5.0) tectonic earthquakes.