First thermal analysis of the caldera and the summit of the volcano complex Peteroa, Mendoza, Argentina.

DARIO TROMBOTTO; PABLO PENAS; JAN HENRIK BLÖTHE

Valdivia

Congreso; International Glaciological Coonference VICC 2010 "Ice and Climate Change": A View from the South; 2010

Summary With the support of the International Center for Earth Sciences (Malargüe) it was possible to overfly the volcanic complex Peteroa (highest peak: 4100 m ASL approximately) with a Cessna equipped with a thermosensible camera AGEMA TVH 550 on March 25, 2009. The volcano is located in the Cordillera Principal at 35º 15’ S and 70º 35’ W. The purpose of this inspection flight was to analyse the temperature of its caldera and of the summit which displays simultaneously volcanic activity, glaciation and neoformation of permafrost. The intention was to register the surface temperature of the summit and to distinguish different thermal areas be it uncovered or covered ice, in the shade or exposed to solar radiation as well as to calculate the temperatures indicating permafrost and areas linked to present volcanic activity. Volcanism is expressed mainly by five large craters with fumaroles and emanations of sulphur and steem. The figured glaciated area (aerial photographs from 1997) was 19 km2. The glaciated surface is characterized by 10 glaciers of different size which occupy part of the summit and its surroundings. The largest glacier is placed on the southern wall of the volcanic complex with a size of 8 km2 approximately. The glaciers are strongly conditioned by the volcanic activity. Geothermal heat at the monitoring site has a gradient of 1 ºC each 2.9 cm (20-80 cm) with rising depth (2007-2008). Mean annual air temperature is – 2.5 ºC (2007-2008) at 3489 m ASL. The surface of possible permafrost was calculated to be of 74 km2.