Awatere Fault

The Eastern section of the fault runs from Molesworth Station to the coast, near White Bluffs, without significant segmentation.^[4] Shallow-crust seismic studies in Cook Strait extend the fault about 20 km (12 mi) beyond White Bluffs into Cook Strait. The Awatere River, occupying the Awatere Valley, follows the trace of much of the eastern section of the fault, giving its name to the whole structure.^{[2]: 375–376}

The Molesworth section appears to have moved twice since about 3000 years ago, in events with slip values of about 6–7 m (20–23 ft).^[5] Trenching at Saxton River at the eastern end of the Molesworth section suggests 8 ruptures since about 6,300 years ago, with an estimated mean recurrence of about 800 years.^[6] Evidence from the eastern section of the fault suggests that there were 9–10 earthquakes in the period from 8610 BP to AD 1848. This gives a mean recurrence interval of 820–950 years.^[7] In 1848 a minimum 110 km (68 mi) length section of the fault ruptured, causing an earthquake of an estimated magnitude of about 7.5 M_w.^[2]: 375 It is possible that up to 140 km (87 mi) of the fault ruptured.^[2]: 379 The rupture appears to have bypassed the Molesworth section of the fault, continuing on the southern strand through Barefell Pass.^[4]

Seismic hazard on the Eastern section is considered low, with only about 150 years since the last major earthquake on that section and an estimated recurrence interval of 600–2500 years.^[3]