Rheological control on the radiant density of active lava flows and domes

During an effusive-extrusive eruption, the capability of an active lava body (flow or dome) to radiate thermal energy depends on how the lava discharge rate is accommodated by the expansion of the magma body and by the cooling of its surface. This feature can be described by a single empirical parameter, defined “radiant density” that, for a given discharge rate, expresses the efficiency of the lava body to change its area and/or to insulate its inner core, thus modulating the heat radiated from the active surface.