Ground Surface Deformations of Klyuchevskoi Volcano, Kamchatka in 1978‒2014 Based on Geodetic Data

Abstract

This paper gives measured quantities, inclined distances, and elevations between geodetic monuments on the northeastern slope of Klyuchevskoi Volcano for the period from 1978 through 2014. Parasitic and summit eruptions were generally preceded by uplifts of the slope, while the termination of an eruption was accompanied by subsidence. The data from the longest series of observations of vertical displacements on the Kirgurich radial line during the period from 1979 to 2014 were used to determine an uplift of the slope that was increasing nearer to the crater. The maximum displacements occurred 2 years before the start of the 1983 parasitic eruption on the Predskazannyi vent and before the 2003–2004 and 2007 summit eruptions. A ground uplift of 12.5 microradians measured on a 17.8-km baseline was recorded in 2007. Farther from the crater, at a distance of 27 km from it, the vertical displacements were insignificant. We show that the measurement stations at heights of 2000 m to 3000 m were subject to deep creep, i.e., a sliding movement. The rates of movement at these stations reached 5–20 cm/yr. Significant horizontal displacements of geodetic monuments occurred near the parasitic eruptions of March 6, 1980 and March 8, 1983. All lines of measurements were observed to shrink by 5 to 20 mm in 1989‒1993 to 2014, indicating a compression for the northeastern slope of Klyuchevskoi Volcano.