The La Garita Caldera was a volcanic caldera located in the state of Colorado, USA. It is also known as the La Garita Supervolcano, and it is famous for its last eruption 26 millions of years ago.
During the 2012 apocalypse, the La Garita entered into a huge super eruption, due to lava forcing its way to the surface when the Earth's core's temperature became so high, destroying the entire state of Colorado and rendering it uninhabitable. This killed millions of people in the area of Colorado and the ash cloud presumably spread around the United States, at the same time as the Yellowstone Ash cloud was.
When the 2012 Tsunamis occurred, the La Garita supervolcano became inactive and was swept away by a gigantic tsunami at the height of 1500 meters, submerging it underwater.