Seismic Events and Tectonic Setting Near Abepura, Indonesia

The region surrounding Abepura in Papua, Indonesia, lies within one of the world's most tectonically active zones. New Guinea occupies the northern margin of the Australian Plate, where it interacts with the Pacific Plate and several smaller microplates. This convergence produces a combination of subduction, collision, and strike-slip faulting that drives frequent moderate to large earthquakes. A magnitude 7.0 earthquake struck on 6 April 2013 at 04:42 local time, centered 260 km west-southwest of Abepura at a depth of 66 km. The event occurred within the crustal section influenced by the ongoing plate boundary deformation. Four hundred days later, a second magnitude 7.0 earthquake took place on 27 July 2015, located 234 km west of Abepura and roughly 98 km from the 2013 epicenter. Both events illustrate the persistent seismic productivity along this segment of the plate margin. Geologically, the area features a complex assemblage of accreted terranes, ophiolites, and sedimentary basins formed during millions of years of convergence. The New Guinea Trench to the north accommodates northward subduction of the Australian Plate, while the Sorong Fault system and related strike-slip structures accommodate lateral motion between the Pacific and Australian plates. Intermediate-depth seismicity, such as the 66 km depth recorded in 2013, commonly reflects slab deformation within the subducting lithosphere. Historical records document repeated strong shaking throughout Papua. The 20th and early 21st centuries include multiple events exceeding magnitude 7, often producing landslides and localized tsunamis along the northern coast. The two recent magnitude 7.0 earthquakes fit within this established pattern of clustered large-magnitude activity. Current monitoring by regional and global networks continues to track aftershock sequences and background seismicity. Improved understanding of fault segmentation and plate kinematics helps refine hazard assessments for communities in the Abepura vicinity.

References

USGS Earthquake Catalog (events 2013-04-06 and 2015-07-27) Geological Survey of Indonesia tectonic summaries Pacific Ring of Fire seismicity reports