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

COLLINI,E.A.; MINGARI,L.; RECKZIEGEL,F.; BEYERLE, G.; BAEZ,W.; ANDRIOLI,M.; FOLCH,A.; ALEXANDER, P.; VIRAMONTE,J.G.

Congreso; WMO 7th International Workshop on Volcanic Ash; 2015

On 13th June 2015 an eruption from Nevados Ojos del Salado volcano (6,879 m), located on the Chile/Argentineborder, was reported. The satellite images showed a ?plume? being emitted fromaround 6 to 9 hours since 13/15UTC. It was detected using Red-Green-Bluesatellite channel splitting techniques from the SEVIRI sensor on board ofMETEOSAT 10. This event was analized with the collaboration of a solid groupthat speciallizes in Central Andes volcanoes. Wearrived to the conclusion that this phenomenom was caused due to resuspensionof ancient pyroclastic deposits from the Bolsón de Fiambalá, located near tothe Ojos del Salado volcanic complex. The dunes of the Bolsón de Fiambalá are mainly product of theeolian reworked pyroclastics materials originated from the Cerro Blanco strong eruptionwhich occurred about 4500 years ago. Then, a question arises if there was an eruption of the NevadosOjos del Salado volcano or a resuspensionevent from the Bolsón de Fiambalá. In order to clarify this situation theFALL3D model was run in eruption mode. The dispersion plume resulting from thismodelling moved north-eastward, as the earlier report mentioned. At the same time, an estimation of the configuration of theFiambalá deposit from field campaigns and satellite data was made in order toobtain the emission sources set to run the FALL3D in resuspension mode. Meanwhile,we processed the satellite images from theSEVIRI sensor on board of METEOSAT 10 provided by the INPE (Instituto dePesquisas Espaciales, Brasil) observing the presence of a ?plume? movingsouth-eastward from the Bolsón de Fiambalá area. We found that the results fromthe ash/dust resuspension FALL3D simulations are in better agreement with the satellitedata. There are a considerable amount of these pyroclastic depositsalong the Andes and they are source offrequent ash/dust storms or remobilization processes that could be masked as aneruption. One of the main conclusions from this experiment is the strong needof a multidisciplinary approach in order to be conclusive.