Session I :
Micro-physics underlying earthquake nucleation and frictional behavior of complex fault zones : observations and simulation

2nd ACES (APEC Cooperation for Earthquake Simulation) Workshop in Japan

An Optimistic interpretation of friction law from thermal-mechanical coupling in shear deformation of viscoelastic material
Masanori Kameyama, Takane Hori, Phil Cummins, Satoshi Hirano, Toshitaka Baba, Koichi Uhira, Yoshiyuki Kaneda


A thermal-mechanical model of shear deformation of a viscoelastic material as a substitute for frictional resistance is presented. We consider shear deformation of one-dimensional layer composed of a Maxwell viscoelastic material under a constant velocity U and constant temperature Tw at the boundary. The strain rate due to viscous deformation depends both on temperature and and shear stress. The temperature inside the layer evolves owing to the competition between frictional heating and conductive cooling. Our results show (i) that the sign of dSIGMA^ss/dU where SIGMA^ss is shear stress at the steady state, changes from positive to negative as U increases, and (ii) that the threshold velocity above which the sign of dSIGMA^ss/dU is negative increases with increasing Tw. These results imply that the downdip limit of seismogenic zones may bemarked by the transition in the sign of dSIGMA^ss/dU due to temperature rise with depth.

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