This type of high-energy lava-seawater explosion -- called a
littoral lava fountain -- begins with the partial collapse of
a lava delta's leading edge. If the subsidence of the delta
submerges part of a lava tube, the confined interaction between
lava and seawater in the tube may cause a series of violent
steam explosions. The explosive activity captured in this
photograph was part of a series of explosions during a 12-hour
period that followed a partial delta collapse on the south
coast of Kilauea on November 24, 1992.
Intermittent lava fountaining lasting 15 to 40 minutes apparently emptied the tube of lava; each fountaining episode was followed by quiet intervals of 20 to 90 minutes duration. During the quiet intervals, the tube gradually refilled with lava and triggered another lava-seawater explosive episode. This series of explosions hurled lava as far as 60 m from the vent.