2006 Fiscal Year Final Research Report Summary
Morphostratigraphic Studies in Testing for Characteristic Earthquakes and in Evaluating for Earthquake triggered Ground Movement
| Project/Area Number |
16500643
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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 |
Geography
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SUGAI Toshihiko The University of Tokyo, Graduate School of Frontier Sciences, Professor, 大学院新領域創成科学研究科, 教授 (90251321)
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| Project Period (FY) |
2004 – 2006
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| Keywords | EARTHQUAKE / ACTIVE FAULT / YORO FAULT SYTEM / FUKAYA FAULT SYSTEM / PALEOSEISMOLOGY / NOBI BASIN / AYASEGAWA FAULT / KUWANA FAULT |
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| Research Abstract |
Two typical reverse fault systems, the Yoro and the Fukaya fault system, and their surrounded areas were selected. Sediment coring and intensive 14C dating for the sediments coupled with geomorphological investigation revealed the following results.
1. Yoro fault system composed of Yoro, Kuwana and Yokkaichi fault, has produced a large earthquake of Mw=8.0 repetitively during Holocene.
2. The earthquake history shows an average recurrence interval of about 1000 years with a standard deviation of around 300 years.
3. Timing of the faulting events of Kuwana and Yokkaichi fault are almost the same during the middle to late Holocene and Yoro, Kuwana and Yokkaichi fault displaced at around 1586 A.D.( Tensyo-historical earthquake) and 745 A.D. (Tenpyo-historical earthquake). This indicates that Yoro fault system is a single behavior segment during the Holocene.
4. Nobi tectonic basin located in the downthrown side of the Yoro fault system has been subsided and filled with fluvial sediments rapidly during the Holocene with a high ratio of around 2mm/y. The flood sediments may remain the subsidence history. Especially comparison among the relative sea level curves reconstructed from core sediments for each individual coring site has potential to reconstruct the tectonic deformation over the basin.
5. Fukaya fault system is composed of Haruna, Takasaki, Fukaya, and Ayasegawa fault. The paleoseismological study revealed Ayasegawa fault is different behavioral segment with much lower activity from the other part of the system.
6. Long term activity of the fault shown by the subsurface geology is in agreement with the late Pleistocene faulting history. Ground penetrating radar survey coupled with arrayed coring is strong tool to clear the subsurface geology and its tectonic deformation in urbanized areas.
7. Relation between the huge scale sediment transport event and earthquake, whether the event was triggered by earthquakes should be studied.
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Research Products
(44 results)
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[Journal Article] New evidence of active folding of the northern Ayasegawa fault, constrained by tectonic geomorphology, borehole stratigraphy and seismic reflection data.2005
Author(s)
Ishiyama, T., Mizuno, K., Sugiyama, Y., Sugai, T., et al.
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Journal Title
Annual report on active fault and paleoearthquake researches 5
Pages: 29-37
Description
「研究成果報告書概要(欧文)」より
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[Book] 日本の地形、中部2006
Author(s)
町田 洋ほか編, 須貝俊彦分担執筆
Total Pages
392
Publisher
東京大学出版会
Description
「研究成果報告書概要(和文)」より
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[Book] 環境のダイナミクス2005
Author(s)
大森博雄ほか編, 須貝俊彦分担執筆
Total Pages
294
Publisher
東京大学出版会
Description
「研究成果報告書概要(和文)」より
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