[S-SS03] New insights in Earthquake predictability: modelling and forecasting

[SSS03-P02] Nonstationary Renewal Model for Forecasting Repeating Earthquakes under Aftershock-Triggering Effects

*野村 俊一¹、田中 昌之² (1.統計数理研究所、2.気象研究所)

キーワード：繰り返し地震、更新過程、ETASモデル

The point process models to predict earthquake occurrences are roughly classified into two types except for the simplest Poisson process; one is the renewal process for repeating earthquakes and the other is the ETAS (Epidemic-type aftershock sequence) model taking the aftershock-triggering effect of every earthquake into account. However, relatively small repeating earthquakes have the characteristics of both models such that they usually recur periodically but their recurrence intervals get much shorter after nearby large earthquakes. We propose a nonstationary renewal process model for such repeating earthquakes that incorporates the aftershock-triggering effect of nearby large earthquakes as a relative change in the loading rate. We apply the proposed model to the repeating earthquake catalog on Pacific Plate subduction zone in the northeastern Japan and evaluate probabilistic forecasts of the next repeating events considering the aftershock-triggering effect of the 2011 Tohoku earthquake.