Littoral lava fountain on active lava delta, Kīlauea, Hawai‘i

Subsidence of the leading edge of a lava delta may trigger lava-seawater explosions that produce fountains of lava and steam that reach heights of more than 100 m (330 ft). The explosions of molten spatter, bombs, and smaller tephra fragments quickly build a circular cone on the subsided lava delta, sometimes in a matter of minutes.