Inferring rate and state friction parameters from a rupture model of the 1995 Hyogo-ken Nanbu (Kobe) Japan earthquake

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

We consider the applicability of laboratory-derived rate-and state-variable friction laws to the dynamic rupture of the 1995 Kobe earthquake. We analyze the shear stress and slip evolution of Ide and Takeo's [1997] dislocation model, fitting the inferred stress change time histories by calculating the dynamic load and the instantaneous friction at a series of points within the rupture area. For points exhibiting a fast-weakening behavior, the Dieterich-Ruina friction law, with values of dc = 0.01–0.05 m for critical slip, fits the stress change time series well. This range of dc is 10–20 times smaller than the slip distance over which the stress is released, Dc, which previous studies have equated with the slip-weakening distance. The limited resolution and low-pass character of the strong motion inversion degrades the resolution of the frictional parameters and suggests that the actual dc is less than this value. Stress time series at points characterized by a slow-weakening behavior are well fitted by the Dieterich-Ruina friction law with values of dc≥0.01–0.05 m. The apparent fracture energy Gc can be estimated from waveform inversions more stably than the other friction parameters. We obtain a Gc ≈ 1.5×l06 J m−2 for the 1995 Kobe earthquake, in agreement with estimates for previous earthquakes. From this estimate and a plausible upper bound for the local rock strength we infer a lower bound for Dc of about 0.008 m.

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Publication type Article
Publication Subtype Journal Article
Title Inferring rate and state friction parameters from a rupture model of the 1995 Hyogo-ken Nanbu (Kobe) Japan earthquake
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/2001JB000294
Volume 106
Issue B11
Year Published 2001
Language English
Publisher American Geophysical Union
Description 11 p.
First page 26511
Last page 26521
Country Japan
City Kobe, Osaka
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