KINEMATIC ANALYSIS OF LARGE-SCALE STRIKE-SLIP FAULTING AND THEIR IMPLICATIONS TO TECTONIC EVOLUTION OF THE BIRDHEAD REGION, PAPUA, INDONESIA
The study is largely based on interpretation of newly acquired 2D seismic data from several locations surrounding Bird’s Head region including Salawati Basin, Cendrawasih Bay and Seram trough. This new interpretation supported by several fieldworks particularly in the Sorong area, Biak and Yapen Islands. Fieldwork mostly concentrated in collecting evidence of fault movement and their geometries. Integration between surface and subsurface data is the key in understanding fault mechanism.
The results of stratigraphy study of the Bird’s Head indicated facies change from carbonate dominated to clastic deposition around 5-8 Ma suggesting major tectonic change. This evidence is parallel by the fact that deformation was also inconsistent indicating by large variation in strain number. Structural pattern suggested strong evidence that Bird’s Head regions was experienced some rotation and also translation resulting from strike-slip faulting deformation. The fault behavior changes along strike showing several steps and bends which result in complex deformation pattern. These results are inline and supported by present-day earthquakes distributions as well as focal mechanism in the region.