![]() ![]() The numerical simulations of lava flow paths are based on our knowledge of Etna's past eruptions, derived from the integration of historical and geological data and by adopting a high-resolution updated digital elevation model (DEM). Numerical simulations are a powerful tool to explore various eruption scenarios, as they can be used to estimate the extent of the lava field, the time required for the flow to reach a particular point and the resulting morphological changes 19, 20, 21. Etna, is founded on the MAGFLOW numerical model for simulating lava flow paths 16, 17, 18. The methodology, developed to achieve a reliable and comprehensive assessment of lava flow hazards at Mt. The final products of our analysis are two long-term hazard maps 8, one for flank and the other for summit eruptions, showing the probability that a certain area will be inundated by future lava flows over a specific time period. Although lava flow hazards could be considered in terms of the cumulative effects of summit and flank eruptions, a better approach is to assess the hazard related to each type of volcanic eruption separately, as they have varying characteristics and impacts. different hypothetical volcanic events, than is possible to observe directly in identifying areas at risk. Our purpose is to give a rigorous statistical treatment of the historical records of summit and flank eruptions and to explore a much wider range of eruptive scenarios, i.e. Etna by combining numerical simulations of lava flow paths, spatiotemporal probability of future vent opening and event probabilities associated with classes of expected eruptions. In particular, we produce lava flow hazard maps for Mt. Here we present an up-to-date methodology for the quantitative assessment of lava flow hazard based on the critical combination of field data, numerical simulations and probability analysis. Some of them are based on a qualitative analysis of historical eruptions 4, 5 other maps estimate the hazard combining the probability of an eruption occurring anywhere on the volcano with the results of lava flow simulations 10, 11, 12, 13, 14, 15. Etna the hazard related to lava flow inundation has been assessed only at the South-East Crater 1, while for flank eruptions different hazard maps have been already proposed. A detailed map showing areas that are likely to be inundated by future lava flows is extremely useful, allowing people living nearby to judge for themselves the relation between potentially dangerous areas and their daily lives. Therefore, a correct assessment is an essential component in reducing the losses due to volcanic disasters. Etna during the last 150 years, is often derived from a poor assessment of the volcanic hazard, allowing inappropriate land use in vulnerable areas 10. The increasing exposure of a larger population, which has almost tripled in the area around Mt. The ever-expanding use of areas near the volcano increases the potential impact of future eruptions on the regional economy and on the health and safety of the inhabitants 5. Recently, tourist facilities in the summit area have been extensively devastated by the 20–2003 lava flow-forming eruptions 9, with serious damage to the local economy. In the last century, the town of Mascali was almost completely destroyed by lava flows in 1928 and the towns of Fornazzo, Randazzo and Zafferana Etnea were threatened in 1979, 19, respectively. Over the last 400 years, the most destructive eruption occurred in 1669 when ∼1 km 3 of lava was erupted in about four months, producing a 17.3 km long tube-fed lava flow field that destroyed several villages and part of the city of Catania 5. However, both summit and flank eruptions are likely to produce lava flows and these are the greatest hazard posed by Mt. ![]() The geological record suggests that summit eruptions are somewhat more probable than flank 8. In future eruptions, one can expect to see one or the other of these eruptive types 6, 7. Etna is characterized by persistent activity from summit craters, consisting of degassing and explosive phenomena associated with fast-moving lava flows 1, 2 and recurrent effusive eruptions from vents located on the flanks of the volcano, producing lava flows that can extend for several kilometres 3, 4, 5. 1) have the potential to cause significant social and economic damage. Depending on their intensity and position, volcanic eruptions at Mt.
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