Acta Vulcanologica - Vol. The dynamics of a lava flow with thermal layering is studied with a two-dimensional model describing a viscous fuid with Bingham rheology, flowing down a slope. We assume that lava is thermally homogeneous under the plug and that heat is transferred through the plug by conduction.
Heat is lost by radiation to the atmosphere at the surface of the flow.
Immediately after the emission of lava from the vent, a thin crust develops at the top of the flow. The surface temperature decreases rapidly, while the inner temperature remains high. As temperature decreases, viscosity and yield stress increase. At the same time, velocity decreases, the crust and the plug thicken and the total flow height increases. The present model, which considers the thermal effect of the plug, generates a higher inner temperature with respect to previous models, in which temperature was assumed constant in each vertical cross section of the flow.