Socompa is a complex stratovolcano that can be found at the border of Chile and Argentina, reaching an elevation of 19,852 feet. This volcano is best known for its avalanche debris deposit, which have formed the Monturaqui Basin on its west side, the most noted example of this type of deposit in the world. It is a difficult volcano to visit, taking at least a day by vehicle traveling from the north or the west. Socompa is also known for the microbial ecosystems that occur near grasses at its volcanic vents. These systems are located at the highest elevation out of all microbial systems in the world.

The avalanche debris on Socompa gives the basin a hilly topography and consists of rotated and slumped toreva blocks, among other types of debris. The collapse that caused the avalanche created an amphitheatre that holds ten square miles of debris, most of which is comprised of ignimbrite and gravels from the substrata below the initial point of collapse. Studies have shown the avalanche was caused by shifting debris from the substrata, which were weak prior to the avalanche, rather than a structural failure of the cone. Prior to this theory and before the eruption of Mt. St. Helens in 1980, it was thought that all debris loads were created by a pyroclastic flow that occurred after a large eruption. It was not until 1985 when Peter Francis and other volcanologists discovered that the effect was caused by an avalanche rather than an eruption.

Image Caption: Salar de Atacama with Socompa volcano in the distance, Chile. Credit: Ana Raquel S. Hernandes/Wikipedia (CC BY-SA 2.0)