The steady lowering of the lava lake within Halemaumau at the summit of Kilauea Volcano has increased the potential for explosive eruptions in the coming weeks.
USGS says if the lava level drops to the level of groundwater beneath Kilauea Caldera, water rushing into the conduit could cause steam-driven explosions.
This type of steam-driven explosions causes risk for the area around Halemaumau and the Kilauea summit.
At this time, USGS cannot say with certainty that explosive activity will occur, how large the explosions could be, or how long such explosive activity could continue.
Primary hazards of concern should steam-driven eruptions occur are ballistic projectiles and ashfall.
Pebble-size rocks could be sent miles from Halemaumau, mostly in a downwind direction. Minor ashfall could occur over much wider areas, even up to several tens of miles from Halemaumau.
Steam-driven explosions typically provide very little warning.
Once the lava level reaches the groundwater elevation, onset of continuous ashy plumes or a sequence of violent steam-driven explosions may be the first sign that activity of concern has commenced.
Residents that live around the Kilauea summit should beware of the risk of ashfall, stay informed of the status of the volcano and area closures and review family and business emergency plans.
The explosion at around 8:30 a.m. on May 9, 2018 was triggered by a rockfall from the steep walls of Overlook crater, and not caused by the interaction of the lava lake with the water table. The lava lake surface is still above the water table.
