Séminaire de Simona Scollo

Integration of observations and models for a better evaluation of tephra fall impact during Etna lava fountains

Dott. Simona Scollo, Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo

The frequent number of explosive events at Mt. Etna, in Italy, over the last ten years, has made necessary the improvement of volcanic ash monitoring and forecasting system at the Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo (INGV-OE). During the most intense phase of lava fountains, eruptive columns rose up to several kilometers above sea level and tephra fallout largely affected the population living on the volcano flanks. In addition, large clasts fell in proximal areas injured tourists and hikers. Roads were covered by ash and the reduced visibility and the slipperiness caused several accidents. Volcanic ash dispersal disrupted, in some cases, airport operations in Catania and Reggio Calabria. In order to give prompt and precise warnings to the aviation and civil protection authorities, a novel system for monitoring and forecasting Etna volcanic plumes is active at INGV-OE since late 2008. The system is based on ground-based instruments (e.g. visible camera, radar, lidar, satellite etc.) able to quantify key eruptive source variables, such as mass eruption rate, grain-size distribution as well as ash cloud concentration in the atmosphere. Volcanic ash plume forecasting is performed by using automatic daily procedures for running models of tephra dispersal and plotting hazard maps of volcanic ash dispersal and deposition for two fixed scenarios (i.e. weak plume scenario (WPS) and strong plume scenarios (SPS)). This system was recently updated to identify the plume scenario based on 1-D plume model, forecast characteristics of tephra deposition using near real time observations and finally, identify the region possibly impacted by large clasts (>5 cm). The new integrated system was tested using data from some lava fountain events occurred between 2011 and 2015.

This talk shows the actions that INGV-OE carries out during volcanic emergencies and describes how novel instruments, approaches and techniques are joint together to give more reliable answers and contribute to hazard mitigation.