On July 25, 2019, a helicopter pilot flying a U.S.Geological Survey mission over Kīlauea noticed an unusual green patch at the bottom of Halema‘uma‘u, the crater at the summit of the volcano.
On July 25, 2019, a helicopter pilot flying a U.S.Geological Survey mission over Kīlauea noticed an unusual green patch at the bottom of Halema‘uma‘u, the crater at the summit of the volcano.
Passengers on the helicopter reported to the USGS Hawaiian Volcano Observatory that the smooth green patch looked like water. But with no reflection from its surface, its origin was questioned: was it water, or was it a flat surface made by ash or rockfall dust tinted green by sulfur minerals or algae?
USGS volcanologists generally agreed that if the patch was water, it would be unusual. Water had never been seen in Halema‘uma‘u since written observations of Kīlauea began nearly 200 years ago. The possibility of water in the crater also renewed hazard concerns that arose during the 2018 volcanic events, namely that explosive eruptions can result from the mixing of magma and surface water.
HVO scientists set about seeking answers. In an overflight of Halema‘uma‘u on Aug. 1, they saw reflections from the pond, confirming that the green patch was indeed water. With that question answered, another important one arose: where is the water coming from?
Continue reading at USGS.
Image via USGS.
