It has been about a year since lava finally stopped flowing from Hawaii’s Kilauea volcano, but now something else is flowing deep inside its summit crater.
On July 25 scientists at the US Geological Survey’s Hawaiian Volcano Observatory (HVO) noticed water pooling at the bottom of the Halema‘uma‘u Crater. A second puddle emerged a week later and during August the little ponds have since grown together to form a deepening milky green lake where there was once a pit of roiling lava just last year.
On Sunday, HVO geophysicist Jim Kauahikaua told local radio station KWXX in Hilo that the water level has been rising at a rate of about three feet per week
Kauahikaua said there are two likely explanations for the rising lake: it could simply be an accumulation of rainwater, or it might be the water table “rebounding” following all the volcanic activity of 2018 and the literal collapse of the crater itself.
“The evidence is sort of leading toward groundwater rebounding,” he explained.”But we don’t yet have accurate measures of the depth and how fast it’s rising.”
HVO scientists have been monitoring the expanding pond from above, but hope to get a sample of the water to analyze soon. The unusual color could be due to absorption of sulfur dioxide gas, which also supports the notion that it is flowing from below rather than falling from the sky.
While it looks more like a puddle than a lake at the moment, Kauahikaua said that based on HVO groundwater level data from nearby, he would expect the water to continue to rise as much as another 150 feet, which would make a pretty significant puddle.
When infrared cameras were trained on the water, it appeared to be as hot as you might expect, measuring about 70 degrees celsius (160 degrees Fahrenheit).
When magma and water meet, there is the potential for violent explosions to result when the liquid turns to steam and expands, creating pressure that is often released by flinging rocks and lava about.
But Kauahikaua says quickly rising magma, which hasn’t been seen at Kilauea for centuries, would likely be needed to create such explosions.
“We’re not very worried,” he said.