Rare lava lake discovered on subantarctic island | Polarjournal

Contrary to popular belief, most volcanoes do not have bubbling lava lakes to throw human sacrificies into them. So far, only 7 such permanent lakes are actually known. Now another has been added to the list, on one of the world’s most remote islands: the volcano Mount Michael on Saunders Island, one of the sub-Antarctic South Sandwich Islands has a bubbling lava lake in its crater that is on average 120 m wide.

The discovery was made using satellite images taken between 2003 to 2018. However, there is no visual confirmation because the volcano has never been climbed before, as co-author Dr. Peter Fretwell of the British Antarctic Survey (BAS) testified in an interview with the BBC. But the data are clear and show a lake between 90 – 215 meters wide inside Mount Michael volcano, made of molten rock. Based on the images, the researchers determined that the lava probably has a temperature between 989 – 1279°C. Geologist and co-author of the study, Dr. Alex Burton-Johnson of BAS explains, “We are delighted to have discovered such an outstanding, rare phenomenon in a British overseas territory. The discovery of the lake enhances our understanding of the volcanic activity and hazards of this very remote island. It has also allowed us to further develop our volcano monitoring techniques.”

The images, originating from three satellite systems, were produced over the course of 15 years and have now been analyzed by computer. They show that at the same place there is always a temperature between <300 ->400°C. This proves the existence of a lake. Image: Gray et al. / BAS

Saunders Island is located in the middle of the volcanically active South Sandwich Islands, in the middle of the South Atlantic Ocean. In the middle of the island rises the 990 meter high, active stratovolcano Mount Michael. Although the island had had been visited several times, it was decided not to climb the volcano. All the information that is available about the top of the volcano comes from overflights or satellite photographs. According to Dr. Fretwell, the activities of the volcano and its activities of the volcano and its glaciological features make an ascent extremely dangerous. dangerous. “The peak is surrounded by a huge snow mushroom, extremely soft snow with a consistency like a cake coating. Probably caused by the continuous ejection of steam from the volcano’s interior. You can’t just and you would have to dig through it (in order to look inside, ed. (to be able to look inside, editor’s note). But that takes time and is very dangerous on an such an active volcano very dangerous.”

The volcano towers over the island, which is inhabited by hundreds of thousands of penguins. The ash floors bear witness to the past activities of the still active volcano. Image: Michael Wenger

Based on the series of images that had been produced by the satellites which showed a constant emission of smoke and steam, plus the images that images that had recorded thermal anomalies inside the crater, the researchers are convinced that the lake is there permanently. But what keeps the lava keeps it liquid, the researchers can only speculate. Dr. Burton-Johnson Dr. Burton-Johnson says: “The lava ejected from the Earth’s interior must be small. the material ejected to the surface and the source of the heat must come from gas. gas. This suggests a very gas-rich volcano.” This would also explain the practical constant steam crest around the volcano’s top, which was described by Fabian von Bellingshausen when he discovered the islands in 1821. had been described. The paper’s lead author, Danielle Gray of the University College London, says of her success, “Mount Michael is a volcano on a very remote island in the Southern Ocean. It is virtually impossible to climb it, and without the high-resolution satellite imagery, it would have been quite difficult to learn more about this incredible geological phenomenon. learn.”

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