New ground-motion prediction equations for significant duration of subduction intraslab and interface earthquakes in Japan

To date, multiple ground-motion prediction equations (GMPEs) for the significant duration (DS) of shallow crustal earthquakes have been proposed, but there are few GMPEs for subduction intraslab and interface earthquakes in Japan, and corresponding spatial correlation models have not been published. To address this issue, we first select ground-motion records with moment magnitude 4 ≤ Mw ≤ 9, rupture distance Rrup ≤ 300 km, and peak ground acceleration ≥ 10 gal based on the K-NET and KiK-net databases. Then, for intraslab and interface earthquakes in the subduction zone, based on previous works, the traditional source duration term is simplified, a depth term is added, and new GMPEs for DS of earthquakes in the subduction zone in Japan are developed. The rationality and reliability of the prediction model proposed in this study are verified by residual analysis and comparison with the previous models. Finally, according to the intra-event residuals, a spatial correlation model of DS is established by using a semivariogram and exponential model. The results show that DS of subduction interface earthquakes is larger than that of subduction intraslab earthquakes on the whole, but the spatial correlation coefficient of subduction interface earthquakes decreases more slowly with increasing separation distance than that of subduction intraslab earthquakes, and the significant duration of the spatial correlation is related to site effects and path effects. The results provide a reference for the development of GMPEs based on nonergodic assumptions, regional seismic hazard analysis and loss assessment.