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Fig. 11 | Journal of Applied Volcanology

Fig. 11

From: Effects of eruption source parameter variation and meteorological dataset on tephra fallout hazard assessment: example from Vesuvius (Italy)

Fig. 11

Effect of the terminal settling velocity on the hazard maps (300 kg/m2). Contour lines represent different probabilities of loading greater than the threshold 300 kg/m2. Total mass is 5× 1011 km, column height of 18 km and diffusion coefficient of 5000 m2/s. Wind dataset is from the ERA-Interim of the ECMWF model between 1991 and 2010. Each frame represents the probability distribution of a simulation with all particles of just one terminal settling velocity. The aim of this plot is to show how the different settling velocity class contribute to the extension of the hazard maps. Maximum extension is obtained for particles with settling velocity of 5 m/s (2,983 km2). In the background are reported the “Red Zone” (hazard from pyroclastic flows and lahars) and the “Yellow Zone” (hazard from ash fallout) of the actual Emergency Plan of Vesuvius (DPC 2015; Regione Campania 2015)

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