English: 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.