This massive littoral, or steam, explosion occurred when hot lava entered the sea along the Kalapana shoreline on the southeast coast of Hawaii. The image shows dark tephra and an explosion of other molten lava fragments showering 100 feet into the air, most likely above an open vent in a lavatube system. The cloud is also showering molten fragments to earth around a vent (unseen here), which eventually forms a cone. Other fragments fall into the sea, where they are carried by ocean currents and deposited in bays to form black sand beaches.