Forecasting lava flow

During an effusive volcanic eruption—one that produces flowing lava, as shown here, as opposed to projectile material or clouds of ash—civil authorities need to know which way and how far the lava will flow so that they can decide whether and when to order evacuations. But lava is a difficult fluid to model, because as it cools, it crystallizes and eventually stops flowing. Robert Wright and colleagues at the University of Hawaii in Honolulu have developed a new model for forecasting lava flows. Their model combines two previously published ones: FLOWGO, which simulates lava’s heat loss to predict how far it will flow before solidifying, and DOWNFLOW, which takes a stochastic approach to predict the lava’s direction. Since DOWNFLOW’s stochastic method is computationally simple—but still accurate—Wright and colleagues’ model yields results much more quickly than other forecasting techniques. Moreover, FLOWGO accounts for the effusion rate—the rate of lava coming out of the ground—which strongly affects the flow length and can change substantially over the course of an eruption. When combined with satellite monitoring of the effusion rate, Wright and colleagues’ model can potentially provide updated forecasts in near real time. (R. Wright, H. Garbeil, A. J. L. Harris, Geophys. Res. Lett., in press.) —Johanna L. Miller