From geological map to volcanic hazard evaluation on Mount Etna, Italy: Methodology and examples based on GIS analyses

摘要

This paper proposes a methodology beginning from the geological map - and using GIS analyses - in order to assess the hazards associated with lava flow activity. The examples here presented derive from a new detailed geological map of Mount Etna's eastern flank. In the recent history of Etna volcano over the last 15,000 years it is possible to distinguish, through the application of high-resolution stratigraphy, more than 130 lava flows along the eastern flank. These field data have been organised into a geographical database in order to enable GIS analyses for hazard evaluation to take place. We have combined geological and digital topographic data, with the locations of human settlements, to create maps showing the interactions between human activity and recent eruptions of Etna. We use this as an analytical tool to assess Etna's future effusive volcanic activity. We have developed a simple, yet effective, algorithm within the GIS software to evaluate lava flow distribution on the eastern flank of Mount Etna, starting with land morphology data and the density of eruptive fractures. Results of this study suggest that the whole area studied is part of the lava flow expansion basin of Etna and that no settlements may be considered really safe in the middle-long term. A preliminary and qualitative hazard map showing effusive activity and lava flows invasion on Mount Etna volcano can be assessed by geological data modelled using GIS software. This GIS methodology can be applied to other volcanoes with similar eruptive styles.