M 7.0; 72 km ESE of Kimbe, Papua New Guinea; (4 Aug 2010) (55km from the swarm center)
M 7.3; New Britain region, Papua New Guinea; (18 Jul 2010) (28km from the swarm center)
M 7.0; 40 km S of Kimbe, Papua New Guinea; (31 Oct 2001) (43km from the swarm center)
Seismic Swarm PS20100805.1: Analysis of Activity Near Kimbe, Papua New Guinea
The seismic swarm designated PS20100805.1 occurred in the New Britain region of Papua New Guinea, centered 116 km southeast of Kimbe. It began at 21:32 UTC on 4 August 2010 and concluded at 02:43 UTC on 6 August 2010, spanning 29 hours and 10 minutes. During this interval, six earthquakes were recorded, with magnitudes ranging from 4.4 to 7.0 and focal depths between 35 km and 55 km.
The sequence initiated with a magnitude 5.0 event at 44 km depth, followed 29 minutes later by the swarm’s largest shock, a magnitude 7.0 earthquake at the same depth. Subsequent events included magnitudes of 5.1, 5.4, 4.4, and a final magnitude 5.0 at 55 km depth. Depths remained relatively consistent in the upper to mid-crust, consistent with regional seismicity patterns driven by plate convergence.
Papua New Guinea lies within the Pacific Ring of Fire, where complex interactions among the Pacific, Australian, Solomon Sea, and South Bismarck plates generate intense seismic and volcanic activity. The New Britain segment features subduction along the New Britain Trench, with the Solomon Sea Plate descending beneath the South Bismarck Plate at rates exceeding 10 cm per year. This tectonic setting produces frequent intermediate-depth earthquakes and occasional shallow swarms associated with stress transfer along the megathrust and overlying crustal faults.
Historical records since 2000 indicate eight prior swarms in the broader Kimbe area, clustered in 2000, 2003, 2005 (two events), 2006 (three events), and this 2010 sequence. The region has also experienced multiple magnitude 7.0+ earthquakes since 2000, including events in 2001, July 2010 (28 km from the swarm center), August 2010 (55 km distant), and October 2018 (93 km distant). These large shocks highlight the persistent strain accumulation along the subduction interface.
The 2010 swarm, anchored by its magnitude 7.0 mainshock, likely reflects triggered slip on adjacent fault segments following regional stress perturbations. Such sequences are common in subduction zones and can precede or follow larger mainshocks, though no additional major events were linked directly to this swarm beyond the listed activity.
References
USGS Earthquake Catalog (earthquake.usgs.gov)
Global CMT Catalog (globalcmt.org)
Geological Survey of Papua New Guinea tectonic summaries