Rapid rotations about a vertical axis in a collisional setting revealed by the Palu fault, Sulawesi, Indonesia.
C. Stevens, R. McCaffrey, Y. Bock, J. Genrich, Endang, C. Subarya, S.S.O. Puntodewo, Fauzi, and Vigny C.
Global Positioning System (GPS) measurements from 1992 to 1995 indicate that left-lateral Palu fault in central Sulawesi slips at a rate of 38 +/- 8 mm/a with a locking depth between 2 and 8 km. From the measured slip rate and the historic seismicity of the fault, we estimate that the Palu fault currently has stored enough strain to produce a Mw > 7 earthquake. The Palu and other nearby faults accomodate rapid clockwise rotation of nearly 4°/Ma of E Sulawesi relative to eastern Sunda. The rotation of east Sulawesi transfers E-W shortening between the Pacific and Eurasian plates to N-S subduction of the Celebes basin beneath Sulawesi.