Fig. 17
Area with probability greater than 5 % of tephra loading equal to 300, 500 and 1000 kg/m2, for different values of the horizontal diffusion coefficient. Figure shows the variation of the hazard area for a diffusion coefficient ranging between 1000 and 10,000 m2/s, for three different loading thresholds. Typically, for Plinian and sub-Plinian eruptions at Vesuvius the diffusion coefficient varies between 3000 and 5000 m2/s, resulting in a variation of less than 6 % of the hazard area