When large rockfalls impact the lava lake
, they trigger explosive events that propel volcanic rock fragments (tephra
) upward. This morning's event was vigorous enough to hurl incandescent fragments onto the rim of Halema‘uma‘u Crater, about 110 m (360 ft) above the lava
lake surface. This Quicktime movie shows some of these fragments flying toward the USGS Hawaiian Volcano Observatory webcam that is perched on the rim of the crater. Rockfalls and subsequent explosive events occur with no warning, and the resulting fragments of hot lava and rocky debris thrown onto the crater rim pose a significant hazard in this area.