ISLANDS OF FOUR MOUNTAINS, ALASKA — Scientists are uncovering evidence that a small group of American island volcanoes are sitting on top of a massive supervolcano that can cause global catastrophes if it ever erupted. Here are the details.


National Geographic reports that a group of volcanoes in the Aleutian Islands has all the makings of potentially being part of one big supervolcano, around the same size as the massive Yellowstone Caldera in Wyoming.


In a study presented to the American Geophysics Union by a team of earth scientists led by John Power of the U.S. Geological Survey, the scientists showed evidence that points to the strong possibility that the six volcanoes collected in an Aleutian island group called the Islands of the Four Mountains are actually standing on the edges of one massive caldera.


A caldera is a large bowl-shaped depression that is left behind after a massive reservoir of magma suddenly empties and the overlying ground collapses.


The scientists say they are uncovering evidence of such a large bowl under the ocean, as well as rock samples and undersea ridges that indicate a cataclysmic volcanic eruption did very possibly cause the depression that rings the six active volcanoes of the island group.


Researchers also pointed at the fact that the high and sustained emission of sulfur dioxide from the group’s central volcano, and the composition of volcanic gases from the six volcanoes, also suggest a shared connection to a larger magma source.