The gigantic Aira caldera is located in Kyushu, Japan. It was formed over 22,000 years ago by a massive eruption of pyroclastic flows equal to the size of 50 Mount St. Helens eruptions. Within the caldera lies Sakurajima, one of Japans most active volcanoes. Sakurajima on and off activity indicate the Aira caldera is still very much active.
