As if we need more heartbreaking good news just now, geologists have reason to suspect that a cluster of islands in Alaska are actually part of a similar interconnected volcanic system seen in the park. Yellowstone National.
Called the Islands of the Four Mountains (IFM), this volcanic archipelago is located along the Aleutian Islands chain. New research by John Power of the US Geological Survey at the Alaska Volcanoes Observatory presents evidence of a “previously unrecognized large caldera” in the IFM, in research to be present December 7 at the AGU Fall 2020 meeting.
The cluster consists of six closely spaced stratovolcanoes named Cleveland, Carlisle, Herbert, Kagamil, Tana, and Uliaga. Stratovolcanoes are what we stereotypically think of when considering volcanoes: high craggy mountains topped by a smoking cone. The area is also dotted with a bunch of small cones and cracks. Of the six mountains, Cleveland has been the most active over the past two decades, creating ash clouds that reach 15,000 to 30,000 feet.
The so-called caldera has escaped detection for so long because it is hidden by recent deposits and the ocean. And indeed, it was not easy for these geologists to gather their evidence.
“We rummaged under the cushions of the sofa for data,” Diana Roman, study co-author and geologist at the Carnegie Institution for Science in Washington, DC, explained in an AGU. declaration. “But everything we’re looking at is a caldera in this region.”
The evidence has been scraped away, as Roman said, by analyzing geological deposits, changes in the area over time, gas emissions, and gravity measurements (which indicate the density of buried rocks), among others. clues. It seems that the IFM is influenced by this hitherto undetected caldera.
Calderas are gigantic underground chambers filled with magma, and they are known to produce some of the most catastrophic eruptions in our planet’s history (in comparison, stratovolcanoes are accompanied by relatively tiny pockets of magma). And indeed, they are often referred to as supervolcanoes for this very reason.
Yellowstone is probably the most recognizable caldera on Earth, because of its size and potential threat. It is not expected to erupt anytime soon, but if it does, the caldera will pour lava over an area spanning 30 to 40 miles (48 to 64 km). These eruptions can also produce large amounts of ash, which can alter climates around the world. Carried by the wind, aerosols of sulfur and light particles of ash would reach the planet and would probably cause “a notable drop in temperatures in the world”, according to in the US Geological Survey.
The possible caldera in the IFM is unlikely to match Yellowstone in terms of size or threat (and many other confirmed calderas exist in the Aleutians), but that is not to underestimate the danger posed by these geological features. . This is a potentially very serious discovery and geologists may eventually have to reclassify IFM volcanoes. The gigantic interconnected volcanic system could erupt in the future and with “serious global consequences”, according to the AGU statement.
In addition to changing the climate, large eruptions can also lead to social unrest and upheaval, as was the case in 43 BCE, when the caldera-fed Alaskan Okmok volcano blew up its pile. Recent research suggests that this eruption indirectly led to the fall of the Roman Republic and the Ptolemaic Kingdom in what is now Egypt. Again, no kidding.
To be clear, that the IFM Islands are part of a caldera is not proven. It is a strong intuition which now needs to be reinforced by further observations.
“Our hope is to return to the Four Mountain Islands and take a closer look at the seabed, study the volcanic rocks in more detail, collect more seismic and gravity data, and sample many other geothermal areas.” , said Roman.
I obviously love science, but this is one case where I really, really hope the scientists are wrong. Seriously, please be wrong.