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FIGURE 1 | Mass distribution inside the eruption column in accordance with Suzuki's (1983) parameterization: s(z) = (1 — z/H) exp [A (2/H - 1)], where s(z) is the normalized mass distribution, H is the column height, A is a dimensionless shape parameter, and z is the vertical coordinate. Relative column height is reported on the y-axis and mace dictribiition on the x-ayie

Figure 1 | Mass distribution inside the eruption column in accordance with Suzuki's (1983) parameterization: s(z) = (1 — z/H) exp [A (2/H - 1)], where s(z) is the normalized mass distribution, H is the column height, A is a dimensionless shape parameter, and z is the vertical coordinate. Relative column height is reported on the y-axis and mace dictribiition on the x-ayie

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4These scenarios are the combination of meteorological and volcanological parameters that best reproduce the observed deposits. Toba-K242 corresponds to the meteorological synoptic fields from 3 to 11 September 2005 rotated 9 anti-clockwise around the vent. » Total grain-size distribution (TGSD) is assumed to be bi-gaussian, with maxima at 7 and «42 and corresponding variances o1 and o2; particle diameters (d) are expressed in ®-unit where d(mm) = 2-®. ©The eruption source is described in a purely empirical way in order to repro- duce the optimal geometrical shape of the deposits using the Suzuki distribution (Suzuki, 1983; Pfeiffer et al., 2005). In this, the eruption column acts as a vertical line source (this simplification is only valid in distal areas). 4 Aggregation is accounted for using a model similar to that of Cornell et al. (1983), assuming that 50% of the 63-44um ash, 75% of the 44-31 um ash, and 95% of the less than 31 um ash fell as aggregated particles, with the diam- eter and density found through the best fit. ® This value is used to convert deposit thickness, in mass loading, and to calcu- late total tephra volume from the total mass, whereas a density of 2500 kg/m? was considered to convert into DRE volume. Table 1 | Best fit results of tephra dispersal inversion for the YTT super-eruption.
4These scenarios are the combination of meteorological and volcanological parameters that best reproduce the observed deposits. Toba-K242 corresponds to the meteorological synoptic fields from 3 to 11 September 2005 rotated 9 anti-clockwise around the vent. » Total grain-size distribution (TGSD) is assumed to be bi-gaussian, with maxima at 7 and «42 and corresponding variances o1 and o2; particle diameters (d) are expressed in ®-unit where d(mm) = 2-®. ©The eruption source is described in a purely empirical way in order to repro- duce the optimal geometrical shape of the deposits using the Suzuki distribution (Suzuki, 1983; Pfeiffer et al., 2005). In this, the eruption column acts as a vertical line source (this simplification is only valid in distal areas). 4 Aggregation is accounted for using a model similar to that of Cornell et al. (1983), assuming that 50% of the 63-44um ash, 75% of the 44-31 um ash, and 95% of the less than 31 um ash fell as aggregated particles, with the diam- eter and density found through the best fit. ® This value is used to convert deposit thickness, in mass loading, and to calcu- late total tephra volume from the total mass, whereas a density of 2500 kg/m? was considered to convert into DRE volume. Table 1 | Best fit results of tephra dispersal inversion for the YTT super-eruption.
FIGURE 2 | (A) Comparison between the thicknesses from the best-fit FALL3D simulations and the field data, at each of the 57 sampling points (see Table S1 in Supplementary Material for grid references and thicknesses). The solid line represents a perfect agreement, and the dotted and dashed black lines mark the region that is different from observed thicknesses by a factor 10 (1/10) and 5 (1/5), respectively. (B) Isopach maps showing YTT ash thickness in centimeters (intervals 0.1, 0.2, 0.5, 1, 2, 3, 5, 10, 20, 30, 50, 100 cm), as modeled using FALL3D.
FIGURE 2 | (A) Comparison between the thicknesses from the best-fit FALL3D simulations and the field data, at each of the 57 sampling points (see Table S1 in Supplementary Material for grid references and thicknesses). The solid line represents a perfect agreement, and the dotted and dashed black lines mark the region that is different from observed thicknesses by a factor 10 (1/10) and 5 (1/5), respectively. (B) Isopach maps showing YTT ash thickness in centimeters (intervals 0.1, 0.2, 0.5, 1, 2, 3, 5, 10, 20, 30, 50, 100 cm), as modeled using FALL3D.
Related topics:
GeologyVolcanologyPhysical VolcanologyExplosive volcanic eruptionsVolcanic ashSuper-eruptionsImpact of Volcanic Eruptions on ClimateTephra dispersalVolcanic impact
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