Ash resuspension related to the 2011–2012 Cordón Caulle eruption, Chile, in a rural community of Patagonia, Argentina

Abstract

The 2011–2012 Cordón Caulle eruption emitted about 1 km3 of rhyodacitic tephra. Dominant westerly winds in the region caused most of the primary tephra to deposit in neighboring Argentina. In addition to the impact of widespread dispersal and fallout of primary tephra during the eruption, Argentinawas also significantly affected by remobilization of the primary ash even several years after the climactic phase of the eruption. In this mixed methods study,we combine aspects of natural and social sciences to characterize the ash resuspension events associated with the 2011–2012 Cordón Caulle deposits and assess the impacts on the Argentinian farming community of Ingeniero Jacobacci in the Patagonian Steppe. Our findings showthe primary importance of wind, rainfall and ash availability in controlling the occurrence and persistence of ash resuspension events. The role played by these variables was also reflected in the seasonal distribution of events observed. Regarding the impacts, our results complement those of earlier studies and demonstrate that ash resuspension events can exacerbate the negative impact of primary tephra fallout events from the time of deposition to many years after the eruption. Only after five years has the environment and the farming community begun to show signs of recovery. Our findings also highlight the importance of assessing ash resuspension events in multi-hazard scenarios involving volcanic and hydrometeorologic hazards.