Sea water rushes into the underground lava tubes and becomes trapped.
It turns into steam in the superheated chamber, and expands up to twenty two times its volume. The steam forces its way out, along with the surrounding lava, creating littoral explosions. The explosions can be heard up to a mile away. High fountaining eruptions of the mid-1980's and Kilauea's first lava flow to reach the ocean in thirteen years. Helicopter footage dominates this program for a spectacular vantage point.