2017 Fiscal Year Final Research Report
Studies on the effect of grain shape and grain size of surface hoar on the stability of avalanche slope
| Project/Area Number |
15K12488
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Natural disaster / Disaster prevention science
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| Research Institution | Hokkaido University of Education |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
中村 一樹 国立研究開発法人防災科学技術研究所, その他部局等, 主任研究員 (50725231)
高橋 庸哉 北海道教育大学, 教育学部, 教授 (60236297)
安達 聖 国立研究開発法人防災科学技術研究所, その他部局等, 特別研究員 (80719146)
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| Research Collaborator |
YASHIRO Yuhei
NAKAJO Rio
FUJITA Kyosuke
TOGASHI Kazuma
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| Project Period (FY) |
2015-04-01 – 2018-03-31
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| Keywords | 表面霜 / 雪崩 / 弱層 / 雪氷災害 / 自然災害 |
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| Outline of Final Research Achievements |
The surface hoar layer is known to be one of the most typical weak layer for dry slab avalanches. In order to investigate the features of surface hoar layer, we developed apparatuses that make surface hoar artificially using circuit wind tunnels. Surface hoar was grown on the snow surface using the high water vapor pressure air and the cooled snow surface on the cooling panel. The shapes of the artificially grown surface hoar crystals were sector, plane, column, cup, and needle.
After growing the surface hoar, new snow particles were piled up on the surface hoar layer. Shear frame tests were carried out after sintering snow. Focus on the results of the grain size was 2 mm or less, the shear frame index tended to decrease with increase the grain size of surface hoar. Cross-sectional observations revealed that small surface hoar crystal was buried under additional snow particles. On the other hand, additional snow particles could not enter the layer of large surface hoar crystals.
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| Free Research Field |
雪氷学，自然災害科学，雪氷災害
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