An inventory of Volcanic Debris Avalanches of the Puna region (Central Andes)

EMILCE BUSTOS; WALTER BAEZ; GIANLUCA NORINI; MARCELO ARNOSIO; PABLO GROSSE; LUCIA CAPRA

Antigua

Congreso; Cities on Volcanoes 12; 2024

Volcanic debris avalanches represent a substantial natural hazard. Notably, even inactive volcanoes remain susceptible to edifice collapse. The Puna region of the Central Andes hosts some of the world's tallest volcanoes and an abundance of sector collapse events. This region is ideal for studying a volcanic debris avalanche because of the low denudation rates, the presence of steep-sloped volcanoes prone to collapse, and the excellent exposure of deposits due to the arid conditions and sparse vegetation. We present a database of the volcanic debris avalanche deposits and associated edifices of the Puna, characterizing their morphometries through DEM analyses. The database architecture is designed to ensure that all contained information is both consistent and comparable, facilitating data analysis. Our methodology encompassed the manual digitization of scars and volcanic debris avalanche deposits, coupled with the calculation of morphometric parameters using the TanDEM-X 12 m resolution DEMs within a GIS framework. Computed parameters include length, width, area, volume of the scars and deposits. Aperture width and angle, height, slope, azimuth, elongation, and closure factor of the scars are measured. Height, declivity, thickness, runout, drop height, and friction coefficient describing the deposits are also calculated. At present, the database comprises ca. 15 avalanche entries, many of which pertain to deposits not previously identified. This database provides insights into the spatial and temporal distribution of avalanches across the Puna. It aids in understanding the relationships between volcanic structures, collapse triggers, tectonic structures, hydrothermal alteration zones, and stability. Such analyses can contribute significantly to hazard mitigation.