Data-Driven Numerical Modeling of the Lava Dome Growth at Volcán de Colima, Mexico During 2007-2009

Magma extrusion, lava dome growth, collapse of domes, and associated pyroclastic flow hazards are among important volcanological studies. Using camera images of the lava dome growth at Volcán de Colima in Mexico between early 2007 and fall 2009 and the data-driven finite-volume numerical modeling, we study here the influence of the rheological properties of magma within the lava dome on its morphology. Our viscosity model incorporates the crystal growth kinetics and depends on the characteristic time of the crystal content growth (or the relaxation time) and the specific lava viscosity factor determining the magnitude of the viscosity. Initially, we analyze how this viscosity factor, the relaxation time, and the rate of lava extrusion influence the morphological shape of the growing dome. Several model scenarios of the lava dome growth are then considered depending on the crater geometry, the conduit location, and the extrusion rates. These rates are determined either empirically by optimizing the best fit between the morphological shape of modeled domes and that of the observed dome or from the recorded lava dome volumes. The maximum height of the modeled lava dome and its horizontal extent are in a good agreement with observations in the case of the empirically-derived extrusion rates. ... mehrDue to the interplay between the lava extrusion and the gravity forces, the dome reaches a height threshold, and after that a horizontal gravity spreading starts to play an essential role in the lava dome evolution. The viscosity of the lava dome (about 1012 Pa s) is higher than the viscosity of lavas from Volcán de Colima estimated experimentally, although the core of the lava dome is less crystalized and less viscous. We consider that the higher viscosity could be associated with magma degassing during the lava dome building.