1998 Fiscal Year Final Research Report Summary
A basic study on volcanic disaster from 'high temperature debris avalanche'
| Project/Area Number |
09680449
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Natural disaster science
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| Research Institution | Kumamoto University |
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Principal Investigator |
WATANABE Kazunori Kumamoto University, Faculty of Education, Professor, 教育学部, 教授 (10040049)
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| Co-Investigator(Kenkyū-buntansha) |
YOKOYAMA Shozo Kumamoto University, Faculty of Education, Professor, 教育学部, 教授 (40015847)
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| Project Period (FY) |
1997 – 1998
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| Keywords | High temperature debris avalanche / Volcanic hazard / Kuju Volcano / Matsunodai debris avalanche deposit / Yufu-dake volcano / Debris avalanche |
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| Research Abstract |
We examined the geological occurrences and characteristics of magnetic polarity of the four debris avalanche deposits in Kyushu. The four examples are Matsunodai debris avalanche deposit of Kuju volcano, Tsukahara debris avalanche deposit of Yufu-dake volcano, Shimabara debris avalanche deposit of Unzen volcano, and Kobayashi debris avalanche deposit of Kirishima volcano. The results are as follows.
1) Matunodai debris avalanche deposit of Kuju volcano
In case of Matsunodai debris avalanche deposit, we examined the magnetic polarity of the many blocks in the deposit, and obtained the evidence that the some big blocks indicate higher temperature than the Curie point, about 500ﾟC, of titan-poor titanomagnetite. This result is very significant for the construction of model for the debris avalanche deposit. The existence of the 'high-temperature debris avalanche' deposit suggests that the possibility of the collapse of cooling lava dome which has high temperature interior. The 'high-temperature debris avalanche' is a new type of the volcanic disaster.
2) Tsukahara debris avalanche deposit of Yufu-dake volcano
In case of Tsukahara debris avalanche deposits, we examined the magnetic polarity of the some blocks in the deposit, but we could not obtain the evidence which indicate the high temperature.
3) Shimabara debris avalanche deposit of Unzen volcano
This deposit was formed by 1792 Collapse of Mayu-yama, Unzen volcano. We could not obtaine the evidence of high temperature for the deposits.
4) Kobayashi debris avalanche deposit of Kirishima volcano
The Kobayashi debris avalanche deposit contains some blocks which have some structures showing the high temperature. It is necessary in future to examine the magnetic characteristics of the blocks in this deposit.
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