A rockfall from the wall of Halemaʻumaʻu Crater impacted the lava lake around 10:20 am, triggering an explosion of spatter and smaller particles. HVO geologists working on the far side of the crater captured the initial moments of the plume rising. The explosion deposited a large amount of spatter around the closed Halemaʻumaʻu visitor overlook. Photo taken Tuesday, April 28, 2015 courtesy of USGS/HVO