16/01/2025

M.Sc Natalya Zeinalova

16:00 Uhr

Effusive eruptions, producing lava flows and lava domes, are among important volcanological studies. Lava flow mostly associated with low viscosity advances on long distances, whereas high viscous lava tends to form lava domes. The first part of this presentation is related to the thermo-mechanical numerical modelling of a lava dome growth at Volcán de Colima (Mexico) from 2007 to 2009. We demonstrate how various heat sources and thermal boundary conditions influence the distributions of the lava temperature, crystal content, viscosity, and velocity. The results show that cooling plays a significant role during long (up to several years) episodes of dome building. The thick carapace developed as a response to a convective-radiative cooling influences the lava dome dynamics preventing its lateral advancement. The latent heat release due to crystallization leads to an increase of the temperature in the lava dome interior and to a relative flattening of the dome. The second part of this talk is dedicated to analysing the influence of rheological models on lava flow morphology and its advancement. The simulations are performed using a depth-averaged numerical model. Newtonian and Bingham thermal models demonstrate similar lava flow morphologies and thickness distributions. The Herschel-Bulkley model results in the shortest flow advancement across all three rheological models. We apply the model to study lava flow during the effusive eruption at Mt. Etna’s in December 2015. We have shown that all rheological models approximate the real lava flow width rather accurately, with the Newtonian model providing the best match for the flow extent and developing the same morphological features as the real lava emplacement. While the Herschel-Bulkley model shows a slight deviation in the lava flow length, the Bingham model fits well the main flow branch, with minor divergence in the upper branches.