2017 Fiscal Year Final Research Report
Evaluation of fault gauge temperature using quartz grains by OSL method
| Project/Area Number |
16K13889
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Geology
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| Research Institution | Hokkaido University of Education |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2018-03-31
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| Keywords | fault gauge / Frictional heat / OSL / quartz grains |
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| Outline of Final Research Achievements |
A method is proposed to estimate the temperature attained by gouge quartz grains during fault movements, based on thermally induced OSL sensitivity changes in the SAR protocol. Quartz grains from the host rock were heated from 20℃ to 440°C to assess the correlation between OSL sensitivity change and the temperature experienced by the grains. The results show that when a quartz sample reaches a temperature of 320°C, the ratio of sensitivity change is about 0.85 and OSL signals are completely reset. Ratios of sensitivity change ranging from 0.2 to 1.2 were used as a geo-thermometer to determine the temperatures attained by fault gouge during fault activity. The degree of the sensitivity change is strongly depending on sample locations in the Aera Fault zone, central Japan. While, quartz grains collected from granite basements in the same area also shows a variation of the sensitivity change depending on the equivalent dose without any thermal events.
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| Free Research Field |
地球科学
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