Seismotectonic model and probabilistic seismic hazard assessment for Papua New Guinea

Abstract

Papua New Guinea (PNG) lies in a belt of intense tectonic activity that experiences high levels of seismicity. Although this seismicity poses significant risks to society, the Building Code of PNG and its underpinning seismic loading requirements have not been revised since 1982. This study aims to partially address this gap by updating the seismic zoning map on which the earthquake loading component of the building code is based. We performed a new probabilistic seismic hazard assessment for PNG using the OpenQuake software developed by the Global Earthquake Model Foundation (Pagani et al. in Seism Res Lett 85(3):692–702, 2014). Among other enhancements, for the first time together with background sources, individual fault sources are implemented to represent active major and microplate boundaries in the region to better constrain the earthquake-rate and seismic-source models. The seismic-source model also models intraslab, Wadati–Benioff zone seismicity in a more realistic way using a continuous slab volume to constrain the finite ruptures of such events. The results suggest a high level of hazard in the coastal areas of the Huon Peninsula and the New Britain–Bougainville region, and a relatively low level of hazard in the southwestern part of mainland PNG. In comparison with the seismic zonation map in the current design standard, it can be noted that the spatial distribution of seismic hazard used for building design does not match the bedrock hazard distribution of this study. In particular, the high seismic hazard of the Huon Peninsula in the revised assessment is not captured in the current building code of PNG.

New Insights Into Crustal Deformation of the Indonesia–Australia–New Guinea Collision Zone From a Broad‐Scale Kinematic Model

“…For example, the high rate and dramatic eastward increase in the rate of convergence of the Ramu‐Markham Fault, which passes near PNG's second‐largest city, Lae, confirms the very high seismic hazard inferred by Ghasemi et al. (2020), based on the earlier kinematic block models of Wallace et al. (2014) and Koulali et al.…”

“…In both cases, these have revealed areas where the hazard level was significantly higher than earlier assessments done without the benefit of detailed kinematic block models. For example, the high rate and dramatic eastward increase in the rate of convergence of the Ramu-Markham Fault, which passes near PNG's second-largest city, Lae, confirms the very high seismic hazard inferred by Ghasemi et al (2020), based on the earlier kinematic block models of Wallace et al (2014) and Koulali et al (2015).…”

“…This is possible even if we allow that accommodation of the relative block motion may be shared with other small-scale parallel faults in New Ireland (Lindley, 2006). The Weitin fault experienced an overlapping rupture in two recent major earthquakes in 2000 and 2019 (Mw 8.0 and 7.7, respectively), and Ghasemi et al (2020) have shown that high seismicity is commensurate with a very high slip rate.…”

“…The Weitin fault experienced an overlapping rupture in two recent major earthquakes in 2000 and 2019 (Mw 8.0 and 7.7, respectively), and Ghasemi et al. (2020) have shown that high seismicity is commensurate with a very high slip rate.…”

Smoothed Gridded Seismicity Effect for Land-Use Development, Case Study: Kalimantan Island, Indonesia

“…This method is applied to background earthquake sources. Background source is a term that refers to an earthquake source with no apparent or definite mechanism (Ghasemi et al, 2020;Irsyam et al, 2020). This study is limited to a magnitude of 4.5 <= Mw <6.5 for depths up to 50 km and the rest Mw> = 4.5.…”