Seismic hazard mapping of Papua New Guinea — 2019 revision

In this study, we performed a probabilistic seismic hazard assessment (PSHA) for Papua New Guinea (Figure 1) to underpin a revision of the seismic zoning map for the national building code of PNG (Figure 2).
To perform PSHA, we compiled a composite catalogue for the period of 1900-2017 (Figure 3). We then developed magnitude conversion equations to homogenize the catalogue in terms of moment magnitude scale (M W , Figure 4). In contrast to previous studies in PNG (e.g. Ghasemi et. al, 2016), we developed a seismotectonic model that includes 18 fault models (Figure 5) combined with the distributed seismicity (Figure 6) to model earthquake sources. Following the classical PSHA methodology, we mapped the seismic hazard in terms of peak ground acceleration (PGA) with 10% probability of exceedance in 50 years (Figure 1). We also computed hazard curves (Figure 7) and uniform hazard spectra (Figure 8) at the location of major population centres in PNG (black circles in Figure 1). Results of this study indicate a high level of hazard in the coastal areas of Huon Peninsula and New Britain–Bougainville regions and a relatively low level of hazard in the southwestern part of Papua New Guinea. To identify earthquake sources that are contributing most to the overall hazard, we performed hazard disaggregation analysis for all of the major localities in PNG (e.g. Figure 9). Results of the hazard disaggregation analysis shows that in the Huon Peninsula region, the frequent moderate to large earthquakes occurring on the Ramu-Markham Fault Zone results in high seismic hazard (Figure 9). The New Britain–Bougainville region also has relatively high seismic hazard. The proximity to the subduction zone of the New Britain Trench is the main influence on the calculated level of hazard