EVALUATION OF THE SIZES OF CRUSTAL MAGMA CHAMBERS BENEATH VOLCANOES AND OF THEIR TIME BEHAVIOR BASED ON THE VOLUME AND COMPOSITION OF ERUPTED MATERIALS AND CHAMBER DEPTH

Abstract

Mathematical modeling was used to study the growth of crustal magma chambers beneath volcanoes due to the melting of the surrounding rocks and the discharge of the molten material during volcanic eruptions. The sizes of magma chambers were estimated for Kamchatkan volcanoes (Klyuchevskoi, Shiveluch, Ilyinskii, Zheltovskii, and Bezymyannyi) with inferences as to the modification, growth, and subsequent diminution of the chambers over time based on the volume and composition of the ejecta and chamber depth. The maximum chamber radius was found to vary between 0.5 and 6.0 km. We estimated the time required for a chamber to reach its maximum size, as well as the duration of its residence in a quasi-stationary state when the chamber temperature is almost constant and the chamber size is close to the maximum. The duration of the quasi-stationary state was found to be as long as a few tens of 1000 years for large volcanoes.