Lava bubble burst explosion on active lava delta, Kīlauea, Hawai‘i

Two bubble bursts explode simultaneously as a consequence seawater mixing with lava in a lava tube beneath surface of a lava delta. Because of the confined conditions in the lava tube, explosive pressures build up as water, heated by contact with molten lava, expands instantly to steam. The explosive energy of the steam is sufficient to blast a hole through the top of the tube and shoot lava onto the surface.