CONICET | Buscador de Institutos y Recursos Humanos

The Lascar volcano (23º22?S.-67º44?W.) with cuasi permanent yellow alert, is the most active volcano of northern Chile. For its proximity to the Argentina-Chilean border and the wind directions characteristic in this region, is the most hazardous volcano for the NW and Central Argentina, especially for the aeronavigation. The most common volcanic events are vulcanian eruptions, that usually affect its proximal area. However, several subplinain-plinian eruption had place in some occasion (1986, 1993) that affected a big area, especially NW and central argentina region covering up of 850.000km2. In this work we use our own unpublished 1993 Lascar subplinian-plinian eruption data information. The largest historical eruption of Lascar volcano, began on 18 April 1993 producing a 20-22km eruptive column above the crater. We reconstruct the ash isopach and calculated the total volumen of the eruption. Also, it was produced grain size distribution from several sample points. The samples were obtained immediately, ensuring there were pristine and unaffected by post-deposition environmental conditions. With this samples, the total grain size distribution was reconstructed. Column heights, eruption times, rate of discharge and other volcanological parameters were obtained since descriptions of the Teacher of the Talabre school located next to the volcano, a privileged witness of this eruption, and own information. With this data, we perform a tephra dispersion simulation using the ATLAS model. Meteorological data from ECMWF ERA Interim reanalysis, obtained from the ECMWF data server, were interpolated at each particle position. The simulation results were compared with field data. Finally, we propose as future work, the elaboration of tephra dispersion hazard map focused on the Lascar volcano.