Cook Strait is crossed by four major faults with a dominating horizontal displacement. One is the Wairau, which lies on the western side of the Wairau Valley, passing into Cook Strait to the east of the Marlborough Sounds and probably continuing along the western side of Kapiti Island. This fault is considered to have been responsible for the extension of the Marlborough Sounds across a one-time linear strait, by bodily moving the western portion of the South Island relatively northwards. The Awatere Fault in the Awatere Valley, South Island, continues in the North Island as the Wellington Fault, again with the western side moving northwards relatively to the eastern. The Clarence Fault of the South Island appears in the North Island as the West Wairarapa Fault, movement on which caused the 1855 earthquake which seriously damaged the infant town of Wellington. The Hope Fault passes across the strait to continue north-eastwards in the East Wairarapa.