1929 Arthur's Pass earthquake

Tectonic setting

New Zealand lies along the boundary between the Australian and Pacific plates. In the South Island most of the relative displacement between these plates is taken up along a single dextral (right lateral) strike-slip fault with a major reverse component, the Alpine Fault. In the North Island the displacement is mainly taken up along the Kermadec-Tonga subduction zone, although the remaining dextral strike-slip component is accommodated by the North Island Fault System. The Poulter Fault runs for approximately 50 km east-northeast from near the confluence of the Bealey and Mingha rivers to the valley of the South Hurunui River. Between 16 km and 36 km of the fault ruptured, with dextral displacement of up to 4 metres and dip-slip displacement of 1–2 metres (North side up).

Effects

Numerous landslides were triggered, damaging the Midland Railway and blocking roads. The highway connecting Canterbury and the West Coast via Arthur's Pass was closed for several months. Many water tanks and chimneys were damaged or toppled. Two years after the earthquake, trampers in the Otahake Valley discovered that a 900m high section of the side of a mountain had collapsed, blocking the valley and sending debris 5 km downstream.

Although () this is one of the ten largest land-based earthquakes to strike New Zealand since European settlement, it was overshadowed by the more deadly 1929 Murchison earthquake a few months later.

References

References

1. Eileen McSaveney. (21 September 2007). "Historic earthquakes".
2. [http://sp.lyellcollection.org:/cgi/content/abstract/290/1/387 Mouslopoulou,V., Nicol,A., Little, T.A. & Walsh, J.J. 2007. Terminations of large strike-slip faults: an alternative model from New Zealand. In: Cunningham, W. D. & Mann, P (eds).Tectonics of Strike-Slip Restraining and Releasing Bends. Geological Society of London, Special Publication, 290; p. 387–415.]
3. Kelvin Berryman, Pilar Villamor. (20 May 2004). "Surface rupture of the Poulter Fault in the 1929 March 9 Arthur's Pass earthquake, and redefinition of the Kakapo Fault, New Zealand". New Zealand Journal of Geology and Geophysics.
4. (1 August 2006). "Fluvial response to large rock-slope failures: Examples from the Himalayas, the Tien Shan, and the Southern Alps in New Zealand". Geomorphology.