The growth of an extrusive dome on Shiveluch Volcano, Kamchatka in 1980–2007: Geodetic observations and video surveys

This paper concerns observations in 1980–2007 of an intracrater extrusive dome growing on Shiveluch Volcano. Information is provided on the main phases in the generation of the lava dome. The rate of growth and discharge of erupted lava are shown to vary over time. The 1980–1981 discharge was very low during the initial phase in the generation of the lava dome, not above 0.1–0.2 million cubic meters per day. When the extrusion began to grow again, the highest discharge of ejecta was recorded in 1993, as much as 1.25 million cubic meters per day. The maximum rates of growth and discharge of ejecta are generally observed during the first few months of extrusion generation following the resumption of the eruptive process. Powerful explosive eruptions that accompany the extrusive process provoke an acceleration of dome growth. The periods of explosive eruptions had discharges three orders of magnitude greater than those during the most productive extrusive periods. This nonuniformity in extrusion generation reflects nonuniformities in magma supply, and also indicates the existence of a shallow magma chamber at depths of 4–6 km.