Attenuation relations of strong ground motions are one of the fundamental components in seismic hazard analyses. We investigated strong ground motion attenuation relations for subduction interface events that were used in the seismic hazard mapping in Papua New Guinea to evaluate their applicability. We selected earthquakes (M≥5.0) that occurred around the Rabaul (RABL) station. We conducted relocation of these events using the modified joint hypocenter determination method to improve hypocenter locations using ISC data. We then selected subduction interface events based on the results of relocation and Global CMT solutions. The magnitude range of the dataset of this study was from 5.0 to 6.2 and the source distance range was from 100 km to 200 km. We computed peak ground accelerations (PGAs) using broadband waveform data recorded at RABL station. We compared them to PGAs predicted from two strong ground motion attenuation relations used in the seismic hazard analysis for Papua New Guinea. The observed PGAs are within the ranges of ±2σ for the predicted PGA from the two models. No significant deviations of dependencies on focal depths and source distances from the attenuation models are inferred.
Keywords: strong ground motion, PGA, attenuation model, hypocenter relocation.