Effect of periodic loading on asperity rupture

我们研究了潮汐应力对日本低频地震和小规模重复地震发生的影响。低频地震具有显著的位相选择性，而小规模重复性地震则没有得到显著的结果。2011年东北大地震后，相选择性特征发生了变化，在假设断层上存在周期性应力扰动以及与速率和状态相关的摩擦的情况下，对凹凸体的破裂进行了数值模拟。在周期应力幅值相同的情况下，当微凸处的断裂能较小时，微凸体破裂的位相选择性更显著。这一结果表明，小重复地震的破裂能可以从相选择性的观测中估计出来。

We investigated the effects of tidal stress on occurrence of low-frequency earthquakes and small repeating earthquakes in Japan. While statistically significant phase selectivity was found for the low-frequency earthquakes, no significant result was obtained for the small repeating earthquakes. The characteristics of phase selectivity changed after the 2011 Tohoku-oki earthquake.Assuming periodic stress perturbation and rate- and state-dependent friction on the fault, we conducted a numerical simulation of asperity rupture. When the amplitude of periodic stress is the same, phase selectivity of asperity rupture is more significant for smaller fracture energy at the asperity. This result indicates that the fracture energy of small repeating earthquakes may be estimated from the observation of phase selectivity.