The newly-formed lake inside Hawaii's Kīlauea volcano is now almost 130 feet deep, 880 feet long and 430 feet wide, the U.S. Geological Survey Hawaiian Volcano Observatory has said. The temperature of the water at the surface is now between 160 and 180 F, with temperatures beneath potentially higher.
The lake was first spotted in July last year and its formation is believed to be linked to the eruptions at Kīlauea in 2018. Initially, an aerial image showed a "green pond" around the size of a pickup truck at the bottom of the Halema'uma'u crater, which sits within the larger Kīlauea Caldera.
Since then, the lake has been getting bigger. In September last year, Jim Kauahikaua, a geophysicist with the Hawaii Volcano Observatory, told Newsweek that the lake appears to be a "rising water table" that may be rebounding after the 2018 eruptions. "If this is groundwater, then it will rise to an equilibrium level about 70 meters (230 feet) above the bottom of the pit," he said at the time.
Steam has been recorded rising from the surface of the water, and Kauahikaua said thermal imaging suggests a temperature of 160 degrees Fahrenheit, "but that is probably a minimum due to atmospheric absorption of thermal energy between the lake and the camera."
In January, after the USGS released more images of the lake, HVO geologist Janet Babb told Newsweek the lake appeared to be around 125 feet wide and 620 feet long. Its depth was estimated to be around 74 feet. Babb also said it is possible lifeforms from the surrounding environment may have entered the lake water.
In its latest update, the USGS said there has been a "slow, incremental increase in depth" at the lake "as groundwater and shallow surface water fills the bottom of Halema'uma'u."
"If the water in the lake rises to the level of the water table measured in a well about a mile away, it could be as much as 100 feet higher than it is now. But it isn't clear that the lake will equilibrate at the same level as the well."
The 2018 eruption at Kīlauea's lower East Rift Zone (LERZ) was the biggest for at least 200 years. The volcano started to erupt in April and continued to do so until August. Magma drained from the volcano and the caLdera collapsed. The eruption, scientists say, has provided an unprecedented view into the volcano's plumbing system—an important insight as the USGS lists Kīlauea as the country's most dangerous volcano.
Discussing what will happen to the lake during the next eruption, Kauahikaua said: "The presence of surface water interacting with rapidly rising magma during the next eruption may lead to minor explosions; however, these are not expected to increase the hazard to the public at this time."
