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标题：Growth of plastic shear zone and its duration inferred from theoretical consideration and observation of an ancient shear zone in the granitic crust
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作者：Hidemi Tanaka ; Bunichiro Shibazaki ; Norio Shigematsu 等
期刊名称：Earth, Planets and Space
电子版ISSN：1880-5981
出版年度：2014
卷号：54
期号：11
页码：1207-1210
DOI：10.1186/BF03353321
出版社：Springer Verlag
摘要：A new model for growth of plastic shear zone is proposed based on the basis of a theory of fluid dynamics coupled with a rheological constitutive function, and is applied to a natural shear zone. Mylonite, ultramylonite and other ductile fault rocks are well known to deform in a plastic flow regime. The rheological behavior of these kinds of rocks has been well documented as a non-linear viscous body, which is empirically described as , where : strain rate, τ: shear stress, Q : activation energy, R : universal gas constant, T : absolute temperature, and A and n are constants. Strain rate- and temperature-dependent viscosity is obtained by differentiating the equation, and simplified by substituting n = 1. Then, substitution of the equation into a diffusion equation, , derives an equation δ = 4[ t/p · A exp(− Q/RT) ] 1/2 , where δ: thickness of active layer of viscous deformation, ν: kinematic viscosity, and ρ: density. The duration of creep deformation along the ancient plastic shear zone (thickness: 0.076 m) is estimated to be around 760 s, in a temperature range from 300 to 500°C. This estimation is rather good agreement with intermittent creep during inter-seismic period, than steady state creep or co-seismic slip.