Seismic Swarm PS20061112.1: Analysis of Activity Near Kimbe, Papua New Guinea

The seismic swarm designated PS20061112.1 occurred in a tectonically active region 178 km east-southeast of Kimbe, Papua New Guinea. This area forms part of the New Britain subduction zone, where the Solomon Sea Plate converges with the South Bismarck Plate. The interaction produces frequent shallow to intermediate-depth earthquakes along the arcuate New Britain Trench.

The swarm initiated at 16:11 on 11 November 2006 and concluded at 16:36 on 13 November 2006, spanning 48 hours and 25 minutes. During this interval, nine earthquakes were recorded. Events began with a magnitude 5.1 shock at 10 km depth on 11 November at 16:11:33, followed by a magnitude 5.2 event at 22:43:44 and a magnitude 5.0 event minutes later, both at 10 km depth. Activity continued on 12 November with a magnitude 5.3 earthquake at 10:35:07, a magnitude 4.2 event at 12:40:13, and a larger magnitude 6.2 shock at 18:21:26 reaching 12 km depth. The sequence extended into 13 November, featuring a magnitude 5.0 event at 11:20:14, another magnitude 6.2 earthquake at 16:12:28 (11 km depth), and a final magnitude 5.2 event at 16:36:41, all at 10 km depth except the noted deeper shocks.

This swarm reflects typical clustered seismicity in the region, where stress transfer along the subduction interface can trigger multiple events over short periods without a single dominant mainshock-aftershock pattern. Depths remained predominantly shallow, consistent with crustal deformation above the subducting slab.

Historical records indicate six swarms have occurred in the vicinity since 1 January 2000. Earlier episodes took place in 2000 (one swarm), 2003 (one swarm), 2005 (two swarms), and 2006 (two swarms, including the present sequence). Such recurrence underscores the persistent seismic productivity of the New Britain arc.

Notable larger earthquakes since 2000 include a magnitude 7.0 event on 10 October 2018 located 119 km east of Kimbe (78 km from the swarm center), a magnitude 7.0 shock on 4 August 2010 situated 72 km east-southeast of Kimbe (92 km from the swarm center), and a magnitude 7.3 earthquake on 18 July 2010 in the New Britain region (92 km from the swarm center). These events illustrate the capacity for occasional great earthquakes amid more frequent moderate swarms.

The geological setting of New Britain features volcanic arcs and thrust faults that accommodate oblique convergence, contributing to both seismic and volcanic hazards. Monitoring of swarm patterns aids in assessing short-term elevated seismicity levels without implying immediate larger rupture potential.

References

SeismoSight internal swarm classification records for PS20061112.1 and associated historical statistics.
USGS Earthquake Catalog for regional strong-event parameters since 2000.