This earthquake occurred as a result of strike-slip faulting within the crust of the Pacific plate, near the eastern foothills of the Southern Alps at the western edge of the Canterbury Plains. The earthquake struck approximately 50 km to the west-northwest of Christchurch, the largest population center in the region, and about 80-90 km to the south and east of the Alpine fault, the current expression of the Australia - Pacific plate boundary through the island.
