Looking down from the helicopter, cracks are visible on the surface...

Looking down from the helicopter, cracks are visible on the surface of the east Kamokuna lava delta. These cracks are reminders that lava deltas are inherently unstable features that can collapse without warning. A lava delta collapse can send tons of hot rock into the sea, generating steam-driven explosions that can hurl fragments of molten lava and solid rock 100s of meters (yards) in all directions—inland and seaward. More information about lava delta hazards is provided in our July 28, 2016, Volcano Watch article (https://volcanoes.usgs.gov/observatories/hvo/hvo_volcano_watch.html?vwi…). Photo by Rick Hazlett, University of Hawai‘i at Hilo.