A Burning Lava Lake Concealed by a Volcano’s Glacial Ice

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Science|A Burning Lava Lake Concealed by a Volcano’s Glacial Ice

Trilobites

Persistent pools of lava are quite rare on Earth, and it took years of satellite images to find this one.

ImageA Burning Lava Lake Concealed by a Volcano’s Glacial Ice
Mount Michael is about 1,000 miles from Antarctica.CreditCreditPete Bucktrout/British Antarctic Survey

While Earth’s surface is peppered with volcanoes, lava lakes appear to be vanishingly rare. Popular imagery of volcanoes may imply that these crowning caldrons of liquid fire are common, but there were thought to be only seven contemporary volcanoes on Earth with persistent lava lakes that have been seen to stick around beyond a single eruptive outburst.

Now, using 30 years of satellite observations, a group of scientists from University College London and the British Antarctic Survey has added an eighth volcano to that list: Mount Michael, a 3,250-foot high stratovolcano on Saunders Island, a frigid outpost a thousand miles from Antarctica, the nearest major land mass.

Monitoring this molten reservoir may improve our ability to somewhat forecast the potential hazards from other volcanoes containing lava lakes that are closer to human populations, said Jani Radebaugh, an expert in planetary satellites at Brigham Young University who was not involved with the study.

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Mount Michael is an active, sputtering volcano that is largely covered in glacial ice. Its slopes are dangerous, and it has never been summited, which means no one has ever peered into its crater. It’s also so far from civilization that “it’s almost like it’s on another planet,” said Rosaly Lopes, an expert in planetary and terrestrial volcanology at NASA’s Jet Propulsion Laboratory who was not involved with the study.

ImageA Burning Lava Lake Concealed by a Volcano’s Glacial Ice
A false color satellite image taken in Jan. 2018 of Saunders Island and the lava lake within the crater of Mount Michael.CreditBritish Antarctic Survey

That meant that finding it required satellite observations and analyses. Starting in the 1990s and early 2000s, some orbital eyes spotted prolonged thermal anomalies that hinted at a lava lake’s existence, but couldn’t prove it. But improved satellite imagery from the Landsat, Sentinel-2 and the Terra missions and better processing techniques have allowed this lake to be conclusively identified in a report published this month in the Journal of Volcanology and Geothermal Research. Its thermal signature could be seen throughout the observation period, suggesting the lake is probably persistent.

The area is often cloudy, and a seemingly constant volcanic plume conceals the lake most of the time. Fortunately, the team collected enough shots of the lake from 2003 to 2018 that clearly showed a crater floor containing a superheated lake 295 to 705 feet across. The lava is also 1,812 to 2,334 degrees Fahrenheit, with the higher end of that range about as hot as lava on Earth seems to get.

This discovery emphasizes the geographic diversity of persistent lava lakes. Others have been found within Ethiopia’s Erta Ale, Antarctica’s Mount Erebus, the Democratic Republic of Congo’s Nyiragongo, Nicaragua’s Masaya, Vanuatu’s Mount Yasur and Ambrym and Hawaii’s Kīlauea.

Video
The Halema’uma’u lava lake in the Kīlauea volcano in May 2018CreditCreditVideo by U.s. Geological Survey-Hawaiian Volcano Observatory

But even persistent lava lakes don’t last forever, says Janine Krippner of the Smithsonian Institution’s Global Volcanism Program and who was not involved with the study. Those at Kīlauea and Ambrym have recently drained following prolific eruptions, underscoring that they can be fleeting.

And why some lava lakes persist is not entirely understood. An open and well-connected plumbing pathway from a cache of magma far below right up to the surface seems to be required, and “that condition seems to be very rare,” said Dr. Radebaugh. Researchers hope that Mount Michael might offer more clues to this puzzle.

As significant as this sub-Antarctic lava lake discovery is, the majority of the world’s eruptive activity is thought to be hiding deep beneath the oceans. If we want to find more lava lakes, then perhaps the seafloor is another extreme frontier we should be more seriously surveying, Dr. Radebaugh said.