Tectonic Summary

The August 4, 2010, M 7.0 earthquake of New Britain, Papua New Guinea, occurred as a result of shallow thrust faulting on or near the plate boundary between the Solomon Sea and South Bismarck microplates that are involved in the accommodation of large-scale convergence between the Australia and Pacific plates in the Woodlark Basin region of the southwest Pacific. At the location of this earthquake, the Solomon Sea microplate moves approximately north relative to the South Bismarck plate at a velocity of roughly 120 mm/yr, thrusting under the South Bismark plate at the New Britain Trench and dipping to the north-northwest. The location, depth, and focal mechanism solutions of the event are consistent with the earthquake resulting from thrust faulting associated with subduction along this plate boundary. The subducting Solomon Sea microplate is seismically active to depths of about 600 km beneath the island.

The New Britain region experiences a high level of earthquake activity, with 16 events of M 7 or larger within 3 degrees (336 km) of this event since 1973. The region also has a history of large earthquakes occurring close together in time; of those 16 events, 12 occurred within several days to months of another nearby large earthquake. On July 18, 2010, two earthquakes (M 6.9 and M 7.3) struck about 25 km to the southwest of the August 4, 2010, earthquake. In November 2000, three earthquakes of M 7.8+ occurred over a 2-day period approximately 275 km to the northeast of the August 4, 2010, earthquake. The first event (M 8.0) caused at least two fatalities, left many people left homeless, and caused widespread damage. The second two events resulted in additional minor damage.

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)

Event Details

Event Map

Tectonic Summary

Tectonic Summary

Historical Magnitude 4.5+ (100km)