The possibility of probabilistic earthquake forecasting could be discussed based on the frictionally heterogeneous fault model.Tidal sensitivity of slow earthquake implies that, at least, slip velocity on a part of plate interface is modulated by tidal stress. Based on a frictionally heterogeneous fault model, velocity-strenghtening area, which can be modulated by tidal stress, exists all around the plate interface. Slip velocity modulation on velocity-strengthening area might affect the generation of earthquakes.

① Effect of tidal stress on earthquake-growth possibility ： Ide et al. (2016, Nature Geoscience)

The size-frequency statistics of regular earthquake obeys a power law (GR law), which is characterized by b value. b value could be interpreted as a probability that large earthquake occurs or that earthquake grows to larger seismic moment. It has been shown that b value could be affected by spring-neap tide. That is, earthquake-growth probability may change with stress perturbation on the fault.

② Non-tidal stress perturbations ： Tanaka et al. (2016, EPS), Tanaka & Yabe (2017, EPS)

Stress perturbations on the fault is not only tidal stress, but also non-tidal long-term ocean movements. Its effect on the plate interface is quantified for the first time. Then it has been shown that it could be important when considering long-term effect.