Seismic Hazards in Papua New Guinea's New Britain Region

Papua New Guinea lies within one of the world's most tectonically active zones, where convergence between the Pacific and Australian plates drives frequent large earthquakes. The island of New Britain, home to Kokopo, experiences intense seismicity due to subduction along the New Britain Trench and associated strike-slip faulting. These processes have shaped the region's geology over millions of years, producing volcanic arcs and deep sedimentary basins alongside high seismic risk.

On 17 November 2000 at 21:01 local time, a magnitude 7.8 earthquake struck 138 km SSW of Kokopo at a depth of 33 km. The event released substantial energy within the subduction interface, consistent with the region's history of megathrust activity. Its location near the trench axis highlights the persistent strain accumulation from plate convergence rates exceeding 10 cm per year.

Subsequent strong events underscore ongoing activity. On 5 May 2015, a magnitude 7.5 earthquake occurred 131 km SSW of Kokopo, only 11 km from the 2000 epicenter and at comparable depth. This quake likely involved rupture on a nearby segment of the plate boundary. Three years later, on 10 October 2018, a magnitude 7.0 event took place 119 km east of Kimbe, situated 67 km from the 2000 rupture zone, reflecting distributed deformation across the broader Bismarck Sea region.

These earthquakes form part of a well-documented sequence since 2000, illustrating how stress transfer can trigger events along adjacent faults. Depths around 30–40 km typically correspond to the seismogenic zone where brittle failure occurs. The proximity of the 2015 and 2000 events suggests possible interaction between neighboring asperities on the subduction interface.

Regional monitoring by national and international networks continues to track aftershock sequences and background seismicity. Such data inform hazard assessments for coastal communities vulnerable to both strong ground shaking and potential tsunamis generated by seafloor displacement.

References

USGS Earthquake Catalog (events 2000–2018)
Global CMT Project focal mechanism solutions
Geological Survey of Papua New Guinea tectonic summaries