Integrating satellite measurements into lava flow hazard predictions: a review

During an effusive eruption a key aim for volcanologists is to predict both the area covered by active lavas as a function of time, and ultimately, when the eruption ends and the hazard associated with the flows subsides. Over the last 50 years, quantitiate methods for foreacasting lava flow length have been developed, some empirical, others deterministic, and the sophistication of these models has increased markedly in recent years with the advent of cost effective distributed computing (i.e. cloud processing) and other technological innovations and advances, such as General Purpose Graphical Processing Units.

At its simplest, a lava flow not limited by supply from the vent flows downhill and eventually cools enough that it becomes too stiff to be ‘pulled’ downhill any further, at which point it stops flowing. The more rapidly the lava exists the vent, the greater the distance from the vent lava can extend before this solidication threshold is crossed. Lava flow simulations require information about the effusion rate, as well as the rate at which the lava loses heat to its surroundings, using this information to estimate when the rheological criteria for flow cessation are met. The simulations also need to know something of the underlying topography, so they know which way ‘downhill’ actually is.

Lava effusion rate, cooling rate, and (even) the underlying topography all vary in time during an eruption, at all temporal scales. Repeated measurements, across the entire flow, are required to resolve these important parameters, and remote sensing (beit from space or the air) has been shown able to do this, with varying degreees of success.

In this presentation, we will review how satellite measurements of lava flows have been used to drive (and validate) simulations of lava flow hazards.