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The Canterbury Earthquakes

The 2010 Canterbury earthquake was felt over much of the South Island and caused damage in Canterbury. An aftershock in February 2011 caused much more damage and killed 185 people.

Early Saturday morning on 4 September 2010, people in Canterbury were woken up by a damaging earthquake. The earthquake triggered many aftershocks including the destructive earthquake on 22 February. The magnitude of the February earthquake was less than in September but caused much more damage because it was closer to the city.

People

Only two people were injured during the September Canterbury earthquake. One person was hurt by a falling chimney and another person was hit by flying glass and taken to hospital. Luckily the earthquake happened

 when most people were home in bed and the streets were almost empty. 

Unfortunately the much more damaging 6.3 magnitude aftershock in February happened at lunchtime. This busy time meant that a lot more people were in the centre of town. The much stronger shaking caused some buildings to collapse. Sadly, 185 people were killed and thousands were injured.

Epicentres

The epicentre of the first earthquake was 40 kilometres west of Christchurch, near the town of Darfield. The earthquake was only 10 kilometres deep. It lasted for about 40 seconds and was felt across the South Island and as far north as New Plymouth in the North Island.

The aftershock on the 22 February was smaller in magnitude than the September earthquake but much more damaging. This is because it was centred near Lyttelton, only 10 kilometres from Christchurch city and only five kilometres deep.

History

There have been earthquakes in Christchurch before. Between 1850 and 1930 there were four medium sized earthquakes in Christchurch. About 100 faults have been found in the area and some are as close as 20 kilometres from the centre of Christchurch. But the 2010 earthquake happened on a fault that no one knew about. Scientists are still learning a lot about where earthquakes can happen.

Many roads in the centre of Christchurch and out in the eastern suburbs were damaged by liquefaction as water was pushed to the surface during the earthquake. Image: LEARNZ. 

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The February 2011 earthquake caused huge rock slides in the Port Hills of Christchurch. Image: LEARNZ.

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Many old churches were damaged beyond repair in the February 2011 Christchurch earthquake. Image: LEARNZ. 

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Roads and infrastucture were badly damaged during the February quake, especially in the centre of Christchurch and out in the eastern suburbs. Image: LEARNZ. 

Why do you think the February 2011 earthquake caused so much damage in Christchurch?