The island of Sulawesi, Indonesia, has been shaped and deformed as a result of collision with the Sula platform, a silver of continental material from the northern margin of Australia-New Guinea. The collision has resulted in rotation of the north volcanic arm of Sulawesi and the development of the accretionary wedge of the North Sulawesi trench. The North Sulawesi trench changes laterally from a zone of no active deformation in the eastern part to a wide accretionary wedge in the west. Early stages of thrusting produce a steep frontal slope (8¿-16¿), indicative of relatively high basal shear stress, whereas the more advanced (western) zone of thrusting produces a gentle (2¿) slope, consistent with low basal shear stress. Reported paleomagnetic data suggest post late Eocene counter-clockwise rotation of the North Arm, and the offshore geophysics are explained by a pivot of the North Arm with respect to the Celebes basin about the eastern end of the arc. Convergence between the North Banda Basin and Southwest Sulawesi is documented by the presence of the Tolo thrust. Its outcrop is strongly acurate and its accretionary wedge varies in width from a minimum of a few kilometers at each end to a maximum of 30--40 km in the central part. The northern end transforms to the left-lateral Matano fault, with a reported offset of 20 km. The sourthern end of the thrust projects toward the deformed rocks of Buton, but the structural relations there are not clear. The Matano fault zone appears to connect westward with the Palu fault, which forms the western transform of the North Sulawesi trench. The Palu-Matano fault system acts as a trench-trench transform between the North Sulawesi trench and the Tolo thrust, and this system is described by the same rotation pole as that for the Sulawesi North Arm.