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地震期间断层的抗滑阻力是地震物理学中的一个关键未知数。实验室中慢滑速率下岩石的摩擦系数为0.6～0.8,与地壳内高应力测量结果一致。我们的研究结果表明,在很高的、地震滑移速率下,地壳硅酸盐岩石摩擦系数的明显降低缘于微观粗糙接触体的强烈“闪速”加热以及由此引起的抗剪强度的衰减。由闪速加热产生的摩擦系数值可以解释沿某些活断层———如圣安德烈斯断层———实测热流异常的缺失。而由闪速加热导致的近乎纯粹的速度弱化摩擦则可以解释地震破裂是如何以自愈合滑动脉冲模式传播的。
The slip resistance of faults during the earthquake is a key unknowns in seismic physics. The coefficient of friction of rocks at slow slip rates in the laboratory is 0.6 to 0.8, consistent with the high stress measurements in the crust. Our results show that the significant reduction of the friction coefficient of crustal silicate rocks at high rates of seismic slip is due to the intense “flash” heating of microscopic rough contacts and the resultant shear strength Decay. The coefficient of friction generated by flash heating can account for the absence of measured heat flow anomalies along certain active faults, such as the San Andreas Fault. The near-pure velocity-weakening due to flash heating can explain how earthquake ruptures propagate in a self-healing slip-pulse mode.