Indication Strike Slip Movement A Part of Sorong Fault Zone in Yapen Island, Papua, Indonesia

Abstract

Sorong Fault Zone is located at northern of the Papua Island. It is moving from the body bird of Papua Island toward south-southeast of Molluca Island, spreading to east part of Celebes Island, and overstepping east part of Yapen Island which occupied the Bird’s Neck of Papua. The fault became a border between Caroline oceanic plate (part of pacific oceanic plate) and Australian continental plate. Instead, The Sorong Fault Zone controlled forming of Salawati Basin in west of Yapen Island. The Sorong Fault, Lengguru Fold thrust belt, Tarera-Aiduna Fault, and Seram Thrust are structural features which associated with the collision between the Australian continental plate and the Pacific oceanic plate at Oligo-Miocene as regional uplift. This paper explains the indication trace of Sorong Fault Zone in research area, there are shear zone, minor fault, brecciation zone, and lineament in Cataclastic Breccia Formation. The research was conducted in the Sumberbaba area, Yapen Timur sub-district, Yapen Waropen district with fieldwork as the main method. The Sumberbaba area is located appropriate in fault line of Sorong Fault Zone. The general structure pattern that worked in research area is northwest-southeast direction with strike-slip movement. The lithologies at the area are Cataclastic Breccia in late Miocene, tuffaceous sandstone and tuffaceous breccias for Volcanic Yapen Formation in late Eocene to early Miocene, limestone for Wurui Formation in early Miocene, and sandstone Kurudu Formation in early Pliocene. Structural analysis in this area was done by using the measurement method of collecting structure evidence. There are shear fracture and extension fracture in rock outcrop. The characteristics of fault should have shear orientation or strike of shear plane, dip direction, and slickenside. The majority of lineaments are in NW-SE direction, lineament orientation at the fault in research area in NW-SE (almost W-E) and it is appropriately following the Sorong Fault Zone.