HVO K2cam image at the time of the 6:06 p.m. collapse on Sept. 8. Interestingly, this collapse did not generate a large explosion—only a small, brownish plume was observed during and immediately after the rocky ledge fell into the lava lake. The next day, HVO geologists noted a dusting of ash on the Halema‘uma‘u crater rim, but found no spatter fragments like those that have been hurled to the crater rim during past large explosions. At the time of the Sept. 8 collapse, the lava lake level was about 53.5 m (176 ft) below the vent rim, too deep to be visible from HVO. Collapses are more common when the lava lake level drops significantly, because support is removed from the crater walls. Photo taken Friday, September 8, 2017 courtesy of USGS/HVO