M 7.0; 72 km ESE of Kimbe, Papua New Guinea; (4 Aug 2010) (41km from the swarm center)
M 7.3; New Britain region, Papua New Guinea; (18 Jul 2010) (26km from the swarm center)
M 7.0; 40 km S of Kimbe, Papua New Guinea; (31 Oct 2001) (64km from the swarm center)
Seismic Swarm PS20100719.1: New Britain Region, Papua New Guinea
The seismic swarm designated PS20100719.1 occurred in the New Britain region of Papua New Guinea, centered approximately 69 km southeast of Kimbe. Registered between 13:04 on 18 July 2010 and 15:34 on 19 July 2010, the sequence lasted 26 hours and 30 minutes and included eight earthquakes. Depths ranged from 28 km to 46 km, consistent with intermediate-depth activity along the regional subduction interface.
This swarm formed part of the broader tectonic environment of eastern Papua New Guinea, where the Solomon Sea Plate subducts beneath the South Bismarck Plate. The resulting convergence produces frequent seismic sequences and volcanic arcs across New Britain and New Ireland. Earthquake swarms in this setting commonly reflect stress migration along the plate boundary or within the overriding crust, rather than a single dominant mainshock-aftershock pattern.
The largest event in the swarm reached magnitude 7.3 at 13:34 on 18 July 2010 at 35 km depth. Subsequent events included a magnitude 6.9 at 13:04 on the same day (28 km depth), followed by six smaller shocks between magnitudes 5.0 and 5.4 through 19 July. Depths remained relatively stable near 35 km for most events, with two slightly deeper shocks at 43 km and 46 km. Such clustering indicates localized release of accumulated strain along the subduction zone.
Historical records since 2000 show seven prior swarms in the same general area, occurring in 2000 (one swarm), 2003 (one), 2005 (two), and 2006 (three). These episodes demonstrate recurrent swarm behavior along this segment of the plate boundary. Strong earthquakes since 2000 further illustrate the region’s high seismicity, including magnitude 7.0 events in 2001, 2010, and 2018, as well as the 7.3 mainshock of July 2010 itself. Several of these events nucleated within tens of kilometers of the 2010 swarm center, underscoring persistent seismic hazard.
The July 2010 swarm contributed to ongoing monitoring of strain accumulation and release in the New Britain subduction zone. Continued observation of similar sequences supports improved understanding of how intermediate-depth earthquakes interact with shallower crustal faults and volcanic systems in this tectonically active margin.