1994 Fiscal Year Final Research Report Summary
Generation of pyroclastic flows and their hazard assessments for Unzen-Fugen-dake Volcano
| Project/Area Number |
05452378
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Natural disaster science
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| Research Institution | Hokkaido University (1994)
Kobe University (1993) |
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Principal Investigator |
UI Tadahide Graduate School of Science, Hokkaido University, Professor, 理学部, 教授 (10007164)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Hiroaki Dept.Natural Environmental Science, Hiroshima University, Associate Professor, 総合科学部, 助教授 (60019495)
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| Project Period (FY) |
1993 – 1994
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| Keywords | pyroclastic flow / Unzen Volcano / volcanic hazard / lava dome / Video footage |
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| Research Abstract |
Major porposes of this research were as follows.
1) To record video footage of surface phenomena for lava dome just prior to discharge of pyroclastic flow.
2) To analyze long-term variation of the process to generate pyroclastic flow.
3) To investigate the depositional structure, succession and distribution of pyroclastic flows.
4) To carry out the comparative geological study for pre-historic analogue of Unzen volcano and the other volcanoes, and to characterize dome-collapse-type pyroclastic flows.
Major results of the research are as follows.
1) Video footage : Detailed video footage for 28 pyroclastic flow events were recorded. More precise model for the generation of dome-collapse type pyroclastic flows was proposed.
2) Long-term variation : Long term variation of dome growth and pyroclastic flow generation was discussed using a database of seismic signal observed at Shimabara Volcano Observatory, Kyushu University.
3) Depositional structure etc : Volcanic activity was still going on. Thus, it was impossible to access the deposit. Only preliminary work was done.
4) Comparative study and hazard assessment : A database for Japanese Quaternary volcano was constructed. Any pyroclastic flow which size exceeds 0.1 cubic km occurs twiceper thousand years in Japan.
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