MODELING AND FORECASTING EXPLOSIVE MAFIC ERUPTIONS: INSIGHTS FROM MT. ETNA 2006 AND BEYOND

Areas of the western United States could be subjected to hazards associated with explosive basaltic volcanism, yet these hazards are relatively understudied. We test whether combined use of the PlumeMoM plume dynamics model and the HySPLIT atmospheric dispersal model can accurately replicate the small, well-documented November 24, 2006, explosive basaltic eruption of Mt. Etna (Italy). Initial simulations captured key characteristics of the plume, such as its southeastern bent-over shape and altitude of 5.5 km a.s.l., but simulations of ash dispersal yielded mixed results. At distal locations (> 5km) grain-size distributions and mass loadings match published field measurements. But, locations near the vent (<5 km) and off the main dispersal axis (>8 km) are poorly characterized, often underrepresenting ash totals. Addition of gravitational density current dynamics within the volcanic plume significantly improved the overall agreement between the modeled and observed deposit. Sensitivity analyses confirmed the importance of including a gravitational density current even for a relatively weak, bent-over volcanic plume like the one observed during the Mt. Etna eruption. Next, we plan to use the coupled model to simulate larger prehistoric explosive basaltic eruptions, like those of Sunset Crater, AZ (~1085 AD, with plumes reaching 27 km in height), and Tecolote volcano, Sonora, Mexico, (27 ka, with plumes ~ 12 & 18 km), where we aim to gain better insights into eruption conditions and their connections to deposit characteristics. This benchmarked model could also serve as a valuable tool for forecasting future eruptions in the southwest region. This aspect is particularly crucial given the presence of numerous basaltic volcanic fields in the area that are not extensively monitored. The potential impact of an eruption similar in size to Sunset Crater, Tecolote, or even a smaller bent-over plume like the one observed during the Mt. Etna eruption in 2006 (5.5 km) would be devastating not only for the local population but also for the aerospace and travel industries.