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1984 Ontake Debris Avalanche Deposit

• Coherent formation
• Holocene (September 14th, 1984, Naganokenseibu earthquake)

• Sedimentary facies: Debris avalanche deposit
• Sedimentary facies (Minor): Flow mound
• Lithofacies: Gravels, Sands

• Thickness: several - a few dozen m
• Volume: 3.4 x 10⁷ km³
• Running distance: ca. 12 km, 9 minutes (average 80 km/h)

• Distribution: Denjogawa river - Korigase - Suzugasawa creek - Nigorikawa river, Otaki city, Kiso county, Gifu pref.

• Takeuchi et al. (1998) Geology of the Kiso-Fukushima District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 94p. (in Japanese with English abstract 4p.)
• Yamada and Kobayashi (1988) Geology of the Ontakesan District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 136p. (in Japanese with English abstract 9p.)