Satellite images uncertainty: eruptions or resuspension? The importance of the multidisciplinary approach. The case of June 13th, 2015 Ojos del Salado false volcanic eruption

ESTELA COLLINI; MINGARI L; FLORENCIA RECKZIEGEL; EMILCE BUSTOS; WALTER BAEZ; ANDRIOLI M; FOLCH ARNAU; ALEXANDER P; VIRAMONTE JOSE G.

Anchorage

Congreso; 7th International Workshop on Volcanic Ash (IWVA/7); 2015

World Meteorological Organization

On June 13th, 2015 an eruption from Nevados Ojos del Salado volcano (6,879 m), located on the Chile/Argentine border, was reported. The satellite images showed a ?plume? being emitted for around 6 to 9 hours since 13/15UTC. It was detected using Red-Green-Blue satellite channel splitting techniques from the SEVIRI sensor on board of METEOSAT 10. This event was analyzed with the collaboration of a solid group that specializes in Central Andes volcanoes. We arrived to the conclusion that this phenomenom was caused due to resuspension of ancient pyroclastic deposits from the Bolsón de Fiambalá, located near to the Ojos del Salado volcanic complex. The dunes of the Bolsón de Fiambalá are mainly product of the eolian reworked pyroclastics materials originated from the Cerro Blanco strong eruption which occurred about 4500 years ago. Then, a question arises if it was an eruption of the Nevados Ojos del Salado volcano or a resuspension event from the Bolsón de Fiambalá. In order to clarify this situation the FALL3D model was run in eruption mode. The dispersion plume resulting from this modelling moved north-eastward, as mentioned by the earlier report. At the same time, an estimation of the configuration of the Fiambalá deposit from field campaigns and satellite data was made in order to obtain the emission sources set to run the FALL3D in resuspension mode. Meanwhile, we processed the satellite images from the SEVIRI sensor on board METEOSAT 10 provided by the INPE (Instituto de Pesquisas Espaciales, Brasil) observing the presence of a ?plume? moving south-eastward from the Bolsón de Fiambalá area. We found that the results from the ash/dust resuspension FALL3D simulations are in better agreement with the satellite data. There is a considerable amount of these pyroclastic deposits along the Andes and they are the source of frequent ash/dust storms or remobilization processes that could be masked as an eruption. One of the main conclusions from this experiment is the strong need of a multidisciplinary approach in order to be conclusive.