一般（設計法，地盤工学の展望，その他）

[21-10-3-01] Grain size distribution of tephra layers at the Towa area, Atsuma town, Hokkaido
-Comparison between JIS method and improved method-

*SHOMA ISHIHARA¹, Satoshi Goto¹, Yube Hiyoshi¹, Yuki Okawara¹, Keyu CHEN¹, Shunji Obata¹, Hiromichi Koyasu², Satoshi Ishimaru², Naoki Watanabe³ (1. University of Yamanashi, 2. Hokkaido Research Organization, 3. Research Institute for Natural Hazards and Disaster Recovery, Niigata University)

Keywords:tephra , grain size characteristics, test method