| Co-Investigator(Kenkyū-buntansha) |
LIED Karstein Sec. Directer, Norwegian Geotechnical Institute, 雪崩調査部(ノルウェー), 部長
NOREM Harald Res. Fell., Norwegian Geotechnical Institute, 雪崩調査部(ノルウェー), 主任研究員
NOHGUCHI Yasuaki Res. Fell., National Res. Center for Disaster Prevention, 長岡雪氷防災研究所, 主任研究官
IIDA Hajime Res. Fell. Kurobe Science Museum, 学芸員
SATO Atsushi Res. Fell., National Res. Center for Disaster Prevention, 新庄雪氷防災研究所, 主任研究官
ABE Osamu Res. Fell., National Res. Center for Disaster Prevention, 新庄雪氷防災研究所雪氷防災第一研究室, 研究員
TERADA Hideki Res. Fell., Public Works Res. Inst., Min. of Construction, 砂防部急傾斜地崩壊研究室, 主任研究員
FUJISAWA Kazunori Res. Fell., Public Works Res. Inst., Min. of Construction, 砂防部急傾斜地崩壊研究室, 研究員
LARSEN Jan Otto Res. Fell., Norwegian Geotechnical Institute, 雪崩調査部(ノルウェー), 主任研究員
BAKKENHOI St 地球工学研究所, 雪崩調査部(ノルウェー), 主任研究員
NAKAMURA Yoshimitsu Res. Fell., Public Works Res. Inst., Min. of Construction, 砂防部急傾斜地崩壊研究室, 室長
FUKUZAWA Takuya Res. Ass., Inst. Low Temp. Sci., Hokkaido Univ., 低温科学研究所, 助手 (90238460)
NISHIMURA Kouichi Res. Ass., Inst. Low Temp. Sci., Hokkaido Univ., 低温科学研究所, 助手 (10180639)
SHIMIZU Osamu Res. Ass., Fac. of Agriculture, Hokkaido Univ., 農学部, 助手 (20178966)
NAKAGAWA Masami Res. Ass., Tohoku University, 工学部, 助手 (80198043)
KAWADA Kunio Res. Ass., Toyama University, 理学部, 助手 (20019003)
NARITA Hideki Lecturer, Inst. Low Temp. Sci., Hokkaido Univ., 低温科学研究所, 講師 (20001662)
IZUMI Kaoru Ass. Prof., Niigata Univ., 積雪地域災害研究センター, 助教授 (50114997)
KIMURA Ryuji Ass. Prof. Ocean Res. Inst., Univ. of Tokyo, 海洋研究所, 助教授 (20013576)
AKITAYA Eizi Professor, Inst, of Low Temp. Sci., Hokkaido Univ., 低温科学研究所, 教授 (20001654)
BAKKEHOI Steinar Res. Fell., Norwegian Geotechnical Institute
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| Research Abstract |
Among two types of snow avalanches the release and dynamic characteristics of wet snow avalanches are rather simple, but those of dry snow avalanches, especially of powder-snow avalanches, are complex and more detailed information is required. The present study was initiated in aiming to make various observations about internal structures and dynamic properties of powder-snow avalanches.
Natural snow avalanches were observed at Shiai-dani in Kurobe Canyon by taking video-films and installing various sensors including impact pressure sensors and ultrasonic anemometer. One of the findings was the record of avalanche winds detected by a ultrasonic anemometer. The avalanche wind was observed to precede the avalanche body.
Snow avalanches were artificially released at Ryggfon site in Norway. So far three avalanches were observed ; in one avalanche the mean running speed was 22 m/s, the volume and maximum depth of the debris were 20, 000 m^3 and 5 m respectively. The observation of size distribution of the constituent snow blocks showed that the larger ones tended to be accumulated at the front part of avalanches.
Laboratory experiments of snow avalanches were also carried out by flowing numerous ice spheres (diameter 2.9 mm) in a 5-m long chute at temperatures from 0 to -30ﾟC. Measurements of velocities and densities of ice spheres showed significant inhomogeneity in the internal structure vertically as well as horizontally.
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