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Scale dependence of rock friction at high work rate
https://nied-repo.bosai.go.jp/records/2902
https://nied-repo.bosai.go.jp/records/2902dceb4640-737b-4428-876e-211b9260108a
| Item type | researchmap(1) | |||||||||||||||||
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| 公開日 | 2023-03-30 | |||||||||||||||||
| タイトル | ||||||||||||||||||
| 言語 | en | |||||||||||||||||
| タイトル | Scale dependence of rock friction at high work rate | |||||||||||||||||
| 言語 | ||||||||||||||||||
| 言語 | eng | |||||||||||||||||
| 著者 |
Futoshi Yamashita
× Futoshi Yamashita
× Eiichi Fukuyama
× Kazuo Mizoguchi
× Shigeru Takizawa
× Shiqing Xu
× Hironori Kawakata
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| 抄録 | ||||||||||||||||||
| 内容記述タイプ | Other | |||||||||||||||||
| 内容記述 | Determination of the frictional properties of rocks is crucial for an understanding of earthquake mechanics, because most earthquakes are caused by frictional sliding along faults. Prior studies using rotary shear apparatus(1-13) revealed a marked decrease in frictional strength, which can cause a large stress drop and strong shaking, with increasing slip rate and increasing work rate. (The mechanical work rate per unit area equals the product of the shear stress and the slip rate.) However, those important findings were obtained in experiments using rock specimens with dimensions of only several centimetres, which are much smaller than the dimensions of a natural fault (of the order of 1,000 metres). Here we use a large-scale biaxial friction apparatus with metre-sized rock specimens to investigate scale-dependent rock friction. The experiments show that rock friction in metre-sized rock specimens starts to decrease at a work rate that is one order of magnitude smaller than that in centimetre-sized rock specimens. Mechanical, visual and material observations suggest that slip-evolved stress heterogeneity on the fault accounts for the difference. On the basis of these observations, we propose that stress-concentrated areas exist in which frictional slip produces more wear materials (gouge) than in areas outside, resulting in further stress concentrations at these areas. Shear stress on the fault is primarily sustained by stress-concentrated areas that undergo a high work rate, so those areas should weaken rapidly and cause the macroscopic frictional strength to decrease abruptly. To verify this idea, we conducted numerical simulations assuming that local friction follows the frictional properties observed on centimetre-sized rock specimens. The simulations reproduced the macroscopic frictional properties observed on the metre-sized rock specimens. Given that localized stress concentrations commonly occur naturally, our results suggest that a natural fault may lose its strength faster than would be expected from the properties estimated from centimetre-sized rock samples. | |||||||||||||||||
| 言語 | en | |||||||||||||||||
| 書誌情報 |
en : Nature 巻 528, 号 7581, p. 254-257, 発行日 2015-12 |
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| 言語 | en | |||||||||||||||||
| 出版者 | Springer Science and Business Media LLC | |||||||||||||||||
| ISSN | ||||||||||||||||||
| 収録物識別子タイプ | EISSN | |||||||||||||||||
| 収録物識別子 | 1476-4687 | |||||||||||||||||
| DOI | ||||||||||||||||||
| 関連識別子 | 10.1038/nature16138 | |||||||||||||||||
