This earthquake occurred in a region considered to have the most complex present-day tectonics on Earth. In the area surrounding Irian Jaya (the western half of New Guinea), four major tectonic plates, the Australian, Sunda, Philippine Sea, and Caroline plates, sandwich half a dozen proposed microplates. The interactions between these microplates produce all possible styles of faulting. This particular earthquake ruptured a strike-slip fault near the boundary of the Bird's Head plate and the recently proposed Maoke plate. In February 2003, three large (M7.0, M7.3, and M6.9) occurred over three days in the epicentral area of the 26 November 2004 shock. Over 600 people were injured and 37 killed due to that sequence.