ALBERT

Description: Lava dome growth is a surface manifestation of the subsurface magma dynamics. We study the dome growth at Volcán de Colima during 2007-2009 using quantitative modelling of history matching. This modelling is based on minimization of misfits between the morphological shapes of modeled and observed domes using model parameters such as the characteristic crystal content growth time and the eruption temperature. We consider two models: (a) a dome growth model where the lava viscosity depends on the volume fraction of crystals, and (b) a thermomechanical model of the dome growth, where the lava viscosity depends on both the volume fraction of crystals and the temperature. In model (a), the evolution of the modelled lava dome for several months agrees well with the observed lava dome. Meanwhile, to match the dome growth for a few years, a highly thin carapace is introduced in the model preventing the dome to significantly advance laterally. The model carapace mimics a colder and more viscous part of the uppermost lava dome. In model (b), we analyse the dome growth depending on the heat transfer at the dome’s interface with the air, conductive heat transfer at the crater’s floor, and the latent heat of crystallization. The carapace develops self-consistently in response to a cooling at the dome’s interface. For dome-building episodes of about few months, dome growth can be well described by a model with crystallization due to degassing. For longer dome-building episodes, cooling plays a significant role in the dome building.