1987 Fiscal Year Final Research Report Summary
MULTIDISCIPLINARY RESEARCH ON FAULT ACTIVITY IN THE WESTERN PART OF THE NORTH ANATOLIAN FAULT ZONE
| Project/Area Number |
62043026
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| Research Category |
Grant-in-Aid for Overseas Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | 調査総括 |
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
HONKURA Yoshimori Tokyo Institute of Technology,Associate Professor, 理学部, 助教授 (00114637)
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| Co-Investigator(Kenkyū-buntansha) |
SATAKE Kenji Tokyo Institute of Technology,Research Assistant, 理学部, 技官 (20178685)
OHSHIMAN Naoto Nihon University,Research Associate, 文理学部, 助手 (70185255)
IKEDA Yasutaka University of Tokyo,Research Associate, 理学部, 助手 (70134442)
TSUKUDA Tameshige University of Tokyo,Associate Professor, 地震研究所, 助教授 (20027288)
MIYAKOSHI Jun-ichiro Tottori University,Professor, 教養部, 教授 (60032116)
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| Project Period (FY) |
1986 – 1987
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| Keywords | North Anatolian Fault Zone / Active Fault / Trenching / Seismic Activiry / Geomagnetic Total Intensity / Self-Potential / Radon / 地震予知 |
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| Research Abstract |
There exists a saismic gap in the western part of the North Anatolian Fault Zone.This fault is separated into two branches in the seismic gap area.The northern branch is characterized by a wide,graben-like structure, while the southern branch shows an active fault of right-lateral strike-slip type.We call the southern branch the Iznik-Mekece fault.We established a local seimsmic observation network and made temporary observations found that seismic activiry is very low at the Iznik-Mekece fault.This is wuite contrary to high seismicity at the northern branch where intermittent earthquake swarms are also notable.The Iznik-Mekece fault may currently be at the stabe of seismic gap of the second kind.Trenching was made at the channel of the small ephemeral stream showing a right-step defiection of about forty meters.The layer below surface soil is composed of colluvium deposits which are underlain by thick mud-flow deposits.The upper colluvium layer has not suffered any disturbances, whereas the lower colluvium layer and the mud-flow layer were disturbed in association with faulting on the Iznik-Mekece fault.The spcimens taken from the umdisturbed layer show the date of about 200 years B.P., indicating that no significant faulting has taken place since 200 years B.P. One specimen specimen showing about 500 years B.P. was found near the bottom of the colluvium laver which suffered disturbances due to faulting.It is concluded that the latest large earthquake at this fault must have taken place 200-500 years B.P.For earthquake prediction studies,continuous monitoring of possible precursoy changes is important.We started continuous measurements of geomagnetic total intensiry and self-potential.Chemical components of groundwater and radon concentration in soil gas have also been measured routinely.
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Research Products
(12 results)
