Paper:

# Conditions for Consecutive Rupture of Adjacent Asperities

## Naoyuki Kato

Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan

Numerical simulation of earthquake cycles is carried out using a three-dimensional infinite uniform elastic model with a planar fault in which frictional stress obeys a rate- and state-dependent law. Two circular asperities with velocity-weakening frictional properties are embedded in a model fault plane, and velocity-strengthening friction is assumed in remaining regions. Different values of the characteristic slip distance __L__ are given to the two asperities so that seismic rupture nucleated at the asperity with smaller __L__ may be arrested at the asperity with larger __L__. Seismic rupture is arrested in the large __L__ asperity for high contrast in __L__ when shear stress at the large __L__ asperity is low. The condition for rupture arrest is examined using a phase plane plot of frictional stress and slip velocity to show that varying effective stiffness of an asperity is important for consecutive rupture. Effective stiffness of an asperity decreases during an interseismic period due to inward propagation of aseismic sliding.

*J. Disaster Res.*, Vol.4, No.2, pp. 106-110, 2009.

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