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Younger Debris Avalanche Deposits

• Coherent formation
• Caldera wall collapse deposit by the activity of Atotsugawa fault
• Holocene (April 9th, April 23rd, June 7th, 1854)

• Sedimentary facies: Debris avalanche deposit
• Sedimentary facies (Upper, Minor): Lahar deposit, Fluvial
• Lithofacies: Sands, Gravels

• Source: Tonbikuzure (Otonbikuzure), west of Mount Tonbiyama
• Thickness: several - 70 m or thicker
• Volume: 1.14 - 2.7 x 10⁸ m³

• Distribution: Dashiwara - Yukawadani valley - Joganjigawa river - Magawa river, Tateyama city, Nakaniikawa county, Toyama pref.

• Harayama et al. (2000) Geology of the Tateyama District, Quadrangle Series, Scale 1:50,000, Geological Survey of Japan, 218p. (in Japanese with English abstract 6p.)