Consequences of volcano sector collapse on magmatic storage zones: insights from numerical modeling

Major volcano flank collapses strongly affect the underlying magmatic plumbing system. Here, we consider the magma storage zone as a liquid pocket embedded in an elastic medium, and we perform numerical simulations in two-dimensional axisymmetric geometry as well as in three dimensions in order to evaluate the consequences of a major collapse event. We quantify the pressure decrease induced within and around a magma reservoir by a volcano flank collapse. This pressure reduction is expected to favour replenishment with less evolved magma from deeper sources. We also estimate the impact of the magma pressure decrease, together with the stress field variations around the reservoir, on the eruptive event associated with the edifice failure. We show that, for a given magma reservoir geometry, the collapse of a large strato-volcano tends to reduce the volume of the simultaneous eruption; destabilization of large edifices may even suppress magma emission, resulting in phreatic eruptions instead. This effect is greater for shallow reservoirs, and is more pronounced for spherical reservoirs than for Email address: [email protected] (V. Pinel) Preprint submitted to Journal of Volcanological and Geothermal ResearchNovember 15, 2012 *Manuscript Click here to view linked References ird -0 07 82 22 2, v er si on 1 29 J an 2 01 3 Author manuscript, published in "Journal of Volcanology and Geothermal Research 252 (2013) 29-37" DOI : 10.1016/j.jvolgeores.2012.11.009