The Lawanopo Fault, central Sulawesi, East Indonesia

The dominant tectonic-force factor in the Sulawesi Island is the westward Bangga-Sula microplate tectonic intrusion, driven by the 12 mm/year westward motion of the Pacific Plate relative to Eurasia. This tectonic intrusion are accommodated by a series of major left-lateral strike-slip fault zones including Sorong Fault, Sula-Sorong Fault, Matano Fault, Palukoro Fault, and Lawanopo Fault zones. The Lawanopo fault has been considered as an active left-lateral strike-slip fault. The natural exposures of the Lawanopo Fault are clear, marked by the breaks and liniemants of topography along the fault line, and also it serves as a tectonic boundary between the different rock assemblages. Inpections of IFSAR 5m-grid DEM and field checks show that the fault traces are visible by lineaments of topographical slope breaks, linear ridges and stream valleys, ridge neckings, and they are also associated with hydrothermal deposits and hot springs. These are characteristics of young fault, so their morphological expressions can be seen still. However, fault scarps and other morpho-tectonic features appear to have been diffused by erosions and young sediment depositions. No fresh fault scarps, stream deflections or offsets, or any influences of fault movements on recent landscapes are observed associated with fault traces. Hence, the faults do not show any evidence of recent activity. This is consistent with lack of seismicity on the fault.