Signs of a supervolcano lurking under Alaska’s Aleutian islands

A group of volcanoes in the Aleutian Islands may form a massive supervolcano similar to Yellowstone. A study by Earth scientists, led by John Power, suggests that six volcanoes in the Islands of the Four Mountains are on the edges of a large caldera. A caldera is a depression formed when a magma reservoir empties and the ground collapses. Evidence, including undersea ridges and rock samples, indicates a past cataclysmic eruption may have caused this formation.

Who led the team of scientists that presented the study to the American Geophysical Union?

What geological features were found that indicate a past volcanic eruption?