Sunken Plunge Pool

When lava is ponded, as in a plunge pool type lava lake below a lava falls, the top portion cools first and forms a crust. The molten material below may drain out, or simply contract during crystallization and cooling. In either scenario, the unsupported crust may then collapse. In this photo a relatively round lava lake’s crust has collapsed into large wedges.

AUTHOR: Dave Bunnell