Development of the Sorong Fault Zone north of Misool Eastern Indonesia

The part of Sorong Fault Zone studied here is located to the north of Misool between Obi and Batanta. The fault zone cuts an Early Miocene collision suture between the Philippine Sea Plate and the northern Australian margin. Its complex
geometry and tectonic history are important for hydrocarbon exploration and to the south of the fault zone are the major oil fields of the Salawati Basin in the Bird’s Head region of Papua. 2D seismic and multibeam seafloor bathymetry data demonstrate the characteristics of the fault zone and basins in the subsurface and at the surface. Three major fault strands of the Sorong Fault Zone are identified: the E–W striking Molucca-Sorong Fault to the north, the NE–SW striking North Sula-Sorong Fault in the middle and NE–SW striking North Misool-Sorong Fault to the south. These faults separate basinal areas which formed by different mechanisms, and as a result have different geomorphological, stratigraphic and structural characteristics. There are significant difficulties in correlating between the basinal areas which have different basement types. An intriguing feature of the fault zone is the variation in seabed expression of different segments. The western Sorong Fault Zone was active very recently although there is currently little seismic activity. There is evidence of both transpression and transtension at different places along the sinistral strike-slip system area. The Kofiau Basin has several features suggesting it could be the northern part of the Salawati Basin
displaced to the west on the Molucca-Sorong Fault during the Pliocene.