Collapse of the unstable walls within Halema`uma`u vent

movie shows two separate rockfalls impacting and disrupting the active lava pond in Halema`uma`u. Rockfalls here result from collapse of the unstable walls of the vent cavity, and are a common occurrence. The first rockfall impacts the lava surface vertically, while the second features small vertical impacts followed by a slide of material that forces the lava surface to slosh towards the north.