PULL-APART BASINS OF SUMATRAN FAULT: PREVIOUS WORKS ANDCURRENT PERSPECTIVES

The Sumatran Fault has been subjected of scientific researches for decades. Katili (1967) is regarded as the earliest work for defining The Sumatran Fault having transcurrent deformation in the light of plate tectonics. Following the work of Katili (1967), Bellier and Sebrier (1994) proposed structural interpretation of Sumatran Fault pull-apart basins using SPOT images. In 2000, Sieh and Natawidjaja published their work concerning neotectonics of Sumatran Fault. Previous works emphasizes on intensive segmentation of Sumatran Fault as distinctive feature. To address the segmentation of Sumatran Fault, concerns should be paid to tectonic evolution of the area. Sumatra was built based upon continental collisions from Late Paleozoic to Late Mesozoic. The collisions generated NW-SE trending basement structure (Barber et al., 2005). Counterclockwise rotation of Sundaland on Middle Miocene triggered the activation of Sumatran Fault in right-handed kinematics. Pre-existing basement structure facilitated the deformation. Sumatran Fault has right-stepping geometry, so that several pullapart basins develop along the fault. This paper concerns with current interpretation of fault configuration based on SRTM data. Interpretation runs from Aceh, Kutacane Graben, Toba Caldera, Tarutung-Sarulla Basins, Barumun-Angkola Segments, Lake Singkarak, Muaralabuh-Sungai Penuh Basins, Musi-Manna Segment, Lake Ranau, Suoh Valley, and Sunda Strait. Fault interpretation aims to classify Sumatran Fault pull-apart basins in terms of structural mechanism and kinematic models. Structural mechanism comprises fault-bend and oversteps basins. Meanwhile, kinematic models emphasizes on fault configuration. New division of Sumatran Fault is proposed, applying structural mechanism as the basis. Sumatran Fault can be packaged in three repetitions of fault-bend mechanism followed by overstep one. Northern, central, and southern structural packages are elaborated in the paper. Kata kunci : Sumatran Fault, Basement Structures, Fault-bend Basin, Overstep Basin, Structural Mechanism, Kinematic Model