Volcanoes claim lives in different ways, by spewing hot ash clouds and projectile tephra or by triggering tsunamis and mudflows. But flowing lava from a so-called effusive eruption does not often endanger life. Since lava rarely flows faster than people can walk, it’s usually easy to get out of the way. But a lava flow destroys all the roads, buildings, and agricultural land in its path, as shown in figure 1. It’s therefore important for scientists to be able to forecast the direction and distance that lava will flow, so that civil authorities can order evacuations or take other appropriate measures.
One precaution that’s sometimes employed is the building of earthen dams to divert lava away from developed or otherwise valuable land. Good forecasts can ensure that the dams, which take time and money to construct, are placed where they will be most effective. But modeling the flow of...
