Lava lake discovered on subantarctic island

Glowing lava on Saunders Island is only the eighth lava lake in the world

Thermal satellite image of the lava lake in the crater of Mount Michael on Saunders Island, a remote volcanic island in the Southern Ocean. © NASA / Landsat
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Sizzling lava surrounded by ice: researchers discovered a glowing lava lake on a volcanic island in the Southern Pole - only the eighth worldwide. The 90 to 215 meter lake is located in the crater of Mount Michael, an active volcano on the uninhabited island. Although there was a long time suspicion that there might be a lava lake in this volcano, only now could the scientists prove this with the help of satellite images.

At first glance, the Antarctic and sub-Antarctic islands in the Southern Ocean seem to be more of a domain of cold and ice than of fire and lava - but that is deceptive. Because under the cold surface this region is volcanically active. Evidence of this is a whole chain of volcanoes under the ice of the West Antarctic, some of which might even be active. Also prominent is the Mount Erebus in the Ross Sea, the southernmost active volcano on earth - and one of the few that have a lava lake.

Aerial view of Mount Michael. © Pete Bucktrout / British Antarctic Survey

Thermal anomaly in the volcano crater

Another of these rare lava lakes has now been discovered by Danielle Gray of University College London and her colleagues on a sub-Antarctic island. The lake is located in Mount Michael, an active volcano on Saunders Island, an uninhabited island that belongs to the British South Sandwich Islands in the Southern Ocean. "The volcano Mount Michael is located on a very remote island and is extremely difficult to reach, " explains Gray.

Earlier, satellite images had hinted at a thermal anomaly in the crater of this volcano. "The resolution of these images was only one kilometer and there was no long-term studies, whether it is a permanent phenomenon, " explain the researchers. To find out if they are just temporary lava outcrops or even a lava lake, Gray and her team have now evaluated new data from Landsat, Sentinel-2 and ASTER satellites.

Lava lake with a thousand degrees hot molten rock

And in fact: "At all 15 times, for which a satellite image was available, a thermal anomaly was detected in the crater in the short-wave infrared range, " the researchers report. The satellites registered surface temperatures of 284 to 419 degrees in a 90 to 215 meter range in the volcano crater. "It's like other lava lakes, " said Gray and her team. display

"This is the first evidence for a lava lake in Mount Michael, " say the scientists. "And it's the first proof of magmatic temperatures. According to their calculations, the magma in the lava lake below the cooler surface must be between 989 and 1.279 degrees. "Identifying the lava lake tempts us more with the volcanic activity of this remote island, but also with the characteristics of this rare phenomenon, " says Gray.

One of only eight worldwide

The newly discovered lava lake in Mount Michael is one of only eight known lava lakes worldwide. The other lava lakes are located in Antarctic Mount Erebus, in Kilauea in Hawaii, in Nyiragongo in the Congo, in the Ethiopian Erta Ale volcano, in the Masaya volcano in Nicaragua and in two volcanoes on the South Sea island of Vanuatu. (Journal of Volcanology and Geothermal Research, 2019; doi: 10.1016 / j.jvolgeores.2019.05.002)

Source: British Antarctic Survey (BAS)

- Nadja Podbregar