M 8.0 - 24 km N of Rabaul, Papua New Guinea

Tectonic Summary

The November 16, 2000, M 8.0 earthquake in the New Ireland region of Papua New Guinea occurred as the result of shallow strike-slip faulting within the interior of the Pacific plate. Focal mechanism solutions for the earthquake indicate that rupture occurred on either a right-lateral northeast-southwest or a left-lateral southeast-northwest-striking fault. Of these two possible fault orientations, finite-fault modeling of globally recorded seismic data is more consistent with slip on the southeast-striking (left-lateral) fault. In this region, the Australia plate moves to the east-northeast with respect to the Pacific plate at a velocity of about 105 mm/yr. At the location of the earthquake, some researchers consider the edges of the Australia and Pacific plates to be divided into several microplates that take up the overall convergence between Australia and the Pacific, including the Solomon Sea, South Bismark, and Manus microplates local to this event. In this context, the November 16th event occurred along the boundary between the South Bismark and Manus microplates.

While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area. Strike-slip events of the size of the November 16, 2000, M 8.0 earthquake are typically about 245x25 km (length x width); modeling of this earthquake implies dimensions of about 150x30 km, predominantly down-dip of the hypocenter.

Shallow earthquakes predominantly represent deformation along plate boundaries and associated structures, rather than within subducted slabs where intermediate-depth and deep earthquakes (70–300 and 300+ km, respectively) occur. This region hosts shallow and intermediate-depth events, and the Australia plate in this region is known to be seismically active to depths of more than 500 km. Within 400 km of the November 16th M 8.0 earthquake, there have been 21 other events of at least M 7 over the preceding 40 years. Two of these events were M 8 or larger. Large-magnitude aftershocks, including the M 7.8 earthquake that occurred only 3 hours later and approximately 100 km to the southeast of the November 16th event, were also associated with this earthquake.

Hayes et al. (2016) Tectonic summaries of magnitude 7 and greater earthquakes from 2000 to 2015, USGS Open-File Report 2016-1192. (5.2 MB PDF)