Kagoshima, Japan sits on the edge of the Aira caldera. The caldera forms the current Kagoshima Bay. When it erupted 22,000 years ago, it spewed 14 cubic miles of material, of which the remains formed the Aira caldera. In comparison, the Mount St. Helens eruption produced only 1/50 of the Aira caldera explosion. The Sakura-jima volcano forms part of the Aira caldera and has been intermittently active. Its activity still causes earthquakes in the area.