2009 Fiscal Year Final Research Report
The possibility of giant eruptions on the Tokara Islands, southern Kyushu, Japan : verification of the suspected submarine calderas
| Project/Area Number |
19340165
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Petrology/Mineralogy/Science of ore deposit
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| Research Institution | Kumamoto University |
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Principal Investigator |
YOKOSE Hisayoshi Kumamoto University, 大学院・自然科学研究科, 准教授 (50230644)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Tetsuo 鹿児島大学, 大学院・理工学研究科, 教授 (70112430)
NAGAOKA Shinji 長崎大学, 教育学部, 教授 (80244028)
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| Project Period (FY) |
2007 – 2009
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| Keywords | トカラ列島 / 海底火山活動 / 海底カルデラ / 琉球弧火山活動 |
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| Research Abstract |
To understand submarine volcanism of the Tokara Islands, Northern Ryukyu arc, we carried out eight submarine exploration cruises with dredge survey. The volcanic rocks recovered from the sea floor and submarine flanks indicate the volcanic activities have occurred during the Quaternary and are distributed widely on the studied area. In situ rhyolitic pumice fragments are found in the vicinity of the circular submarine depressions, ～15km in diameter. Occurrence and geochemical characteristics of the recovered samples suggest strongly huge eruptions of forming a gigantic submarine caldera on the Tokara Islands. The geochemical characteristics of the samples imply that volcanisms and hydrothermal activities on the Tokara Islands could be controlled by the irregular geometry of the subducting Philippine Sea Plate.
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