Earthquake Commission IQ

Risk Maps

Central and Southern South Island

Map

Risk in the Central and Southern South Island Region

Canterbury and West Coast regions'  proximity to the Alpine Fault, puts them at risk from earthquakes. The fault is the surface expression of the collision zone between the Australian and Pacific Plates. This process of collision has thrust up the Southern Alps and caused several large earthquakes. Earthquakes in September 2010 (magnitude 7.1) and February 2011 (magnitude 6.3), accompanied by many strong aftershocks, devastated the central business district and eastern suburbs of Christchurch. The February earthquake killed more than 180 people.

Historically, earthquakes have happened with regularity in this region. In 1717 AD one caused movement along a 375 kilometre stretch of the fault.

In 1888 a magnitude 7.2 earthquake in North Canterbury damaged buildings. Then in 1901 an earthquake of magnitude 6.9 struck Cheviot and a baby was killed when a sod hutt collapsed.. There was widespread damage, although not as serious as in the 2010 and 2011 earthquakes, , to stonework and chimneys around Christchurch.

Along the coasts there is the risk of tsunami, both from those generated far away across the Pacific near South America and from those generated in the ocean close to New Zealand. The 1960 Chilean earthquake generated a 5.5 metre tsunami in Lyttelton, which poured over the walls of the dry-dock.

As has been seen regularly since the turn of the century, movement of the alpine Fault in Fiordland can generate large earthquakes that affect much of the Otago and Southland regions. In 2003  a magnitude 7.2 earthquake centred near Secretary Island lifted the seabed significantly and triggered more than 200 landslides.
There have been tsunamis on the Otago and Southland coasts. In 1820 there was a 10 metre wave in Foveaux Strait, reputedly drowning many Maori walking along the beach near Orepuki.

Past Events

Christchurch - earthquake 04/09/2010 Magnitude 7.1

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