Fig. 4

Field photographs of proximal deposits within 7 km of the vent. a View of Nakadake crater from site IG (6.4 km from vent). The ground 2–3 km from the vent remained green, suggesting incomplete coverage by the gray fall deposit. b The baseball field at site IG was completely covered by the gray fall deposit. Note the absence of the deposit where we removed a coarse lapilli particle (white area to the right of center), suggesting that coarse lapilli were among the first clasts to fall. Scale bar 1 cm. c Upper surface of a lapilli particle at site IG, containing accretionary pellets of type AP1 (white arrow marks) and AP3. d AP3 deposited on the upper surface and the side of a concrete wall at the baseball field (site IG). AP1/2 were covered by AP3, although particles that fell under the net fence were not covered. e Coarse lapilli particles that broke a window and fell inside a building at the Aso youth intercommunion house (site ASK, 4.4 km from vent). Fine ash particles coated the lapilli particles, although to a lesser degree less than those that fell outside the building. f Lapilli and AP3 that fell at site SES (7.5 km from vent). Fewer AP3 were deposited relative to site IG (6.4 km) and the ground was not completely covered by the fall deposit. All locations are shown in Fig. 2