Abstract

Since the eruption and collapse of Mount Saint Helens on May 18th, 1980, volcanic debris avalanches have been described as catastrophic events related to the evolution of volcanic edifices. They have large run-outs, can mobilize several km3 of material and resulting deposits (i.e., volcanic debris avalanche deposits; VDAD's), and have features related to the physical conditions of the avalanche flow and the paleotopography of the area prior to the collapse. The geoforms of VDAD's, such as Toreva blocks, hummocks, levees, ridges and combinations of these generate significant geomorphological features associated with the evolution of volcanic environments. In the Central Andes, between 18 degrees and 25 degrees S, VDAD's and their geoforms are well preserved due to the arid climate of the region, whilst these deposits vary in size and distribution. In this work we review the main geomorphological features of significant deposits generated by the collapse of Quaternary volcanic structures in the Central Andes (Parinacota, Tata Sabaya, Irruputuncu, Ollag & uuml;e, Socompa, Llullaillaco and Lastarria). We describe the main geoforms and internal features that can be recognized (e.g., blocks, faults and folds), to understand processes and hazards related to the growth and destruction of volcanic edifices.