P. Spudich
G. C. Beroza
Mariagiovanna Guatteri
2001
<p><span>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 </span><i>Ide and Takeo's</i><span> [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 </span><i>d<sub>c</sub></i><span> = 0.01–0.05 m for critical slip, fits the stress change time series well. This range of </span><i>d<sub>c</sub></i><span> is 10–20 times smaller than the slip distance over which the stress is released, </span><i>D<sub>c</sub></i><span>, 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 </span><i>d<sub>c</sub></i><span> 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 </span><i>d<sub>c</sub></i><span>≥0.01–0.05 m. The apparent fracture energy </span><i>G<sub>c</sub></i><span> can be estimated from waveform inversions more stably than the other friction parameters. We obtain a </span><i>G<sub>c</sub></i><span> ≈ 1.5×l0</span><sup>6</sup><span> J m</span><sup>−2</sup><span> 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 </span><i>D<sub>c</sub></i><span> of about 0.008 m.</span></p>
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10.1029/2001JB000294
en
American Geophysical Union
Inferring rate and state friction parameters from a rupture model of the 1995 Hyogo-ken Nanbu (Kobe) Japan earthquake
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