Effect of periodic loading on asperity rupture

研究了潮汐应力对日本低频地震和小重复地震发生的影响。低频地震的相位选择性有统计学意义，而小的重复地震的相位选择性无统计学意义。相位选择性特征在2011年东北地震后发生了变化。假设周期性应力扰动和断层上速率和状态相关的摩擦，我们进行了粗糙破裂的数值模拟。在周期应力幅值相同的情况下，粗口处的断裂能越小，粗口断裂的相选择性越明显。这一结果表明，可以通过相选择性观测来估计小重复地震的断裂能。

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.