Socompa is known for its large debris avalanche , which was formed 7,200 years ago when most of the northwestern slope collapsed and slid down , forming an extensive deposit . It was at first considered to be either a moraine or a nuee ardende deposit , until the 1980 eruption of Mount St. Helens prompted awareness of the instability of volcanic edifices and the existence of large scale collapses on them . The Socompa collapse is among the largest known with a volume of and covers a surface area of , and its features are well preserved by the arid climate . Notable are the large toreva blocks which were left behind within the collapse crater . After the landslide , the volcano was rebuilt by the effusion of lava flows and much of the scar is now filled in
1980 eruption of Mount St. Helens
1980 eruption of Mount St. Helens
Socompa