1986 Fiscal Year Final Research Report Summary
ON THE FORMATION OF ICE RAMPARTS IN EASTERN HOKKAIDO
| Project/Area Number |
60580195
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
自然地理学
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| Research Institution | Hokkaido University of Education |
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Principal Investigator |
SASAKI Tatsumi Assistant Professor, Kushiro College, Hokkaido University of Education, 教育学部, 助教授 (80133784)
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| Project Period (FY) |
1985 – 1986
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| Keywords | Ice rampart / Ice action / Thermal ice movement / 氷の熱収縮 / 御神渡り |
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| Research Abstract |
1. Distribution of Ice Ramparts
Ice ramparts were developed on the shores of Lake Kussharo, Lake Toro, Lake Abashiri and Lake Furen. These ice ramparts were commonly composed of sand and gravel. Some of them were covered with grass(old ice ramparts) and the others were bare(new ice ramparts). No ice ramparts were developed on the shores of Lake Saroma, Lake Notoro and Lake Tofutsu.
2. Thermal Ice-Movement
The formation of ice ridges caused by the thermal expansion of lake ice was confirmed by the field survey in Lake Kussharo and Lake Toro. No traces of distinctive thermal ice-movement were found in other lakes.
3. Field Observation on Thermal Ice-Movement in Lake Kussharo
Thermal expansion of lake ice took place in the daytime; the resultant ice movement was shoreward. On the other hand, thermal contraction of lake ice took place during the night; the resultant ice-movement was lakeward. The cumulative expansion of lake ice in the winter of 1985-86 was approximately 3 m.
4. New Ice Ramparts
New ice ramparts were developed on the shores of Lake Kussharo and Lake Toro. Lake ice-movements in these two lakes supplied these ice ramparts with the lacustrine shore material, that is, these ice ramparts are growing under modern climatic conditions.
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