Effects of the Canterbury Earthquakes

State of national emergency

The Canterbury earthquakes are not the largest earthquakes in New Zealand's history, but the February quake has lead to more costly damage than for any other natural disaster in New Zealand.

After the first Canterbury earthquake the National Crisis Management Centre in the basement of the Beehive in Wellington was activated. Civil Defence declared a state of emergency for Christchurch, the Selwyn District and the Waimakariri District. The February earthquake led to a state of national emergency. This meant that trained people from many different organisations from across the country could work on making the area safe again by:

• inspecting buildings
• placing cordons and making sure people did not enter unsafe areas where parts of buildings could collapse
• stabilising buildings
• getting water trucks to areas with no water supply
• removing silt and sand from roads and properties where liquefaction had occurred
• repairing water and sewage pipes
• repairing roads and diverting traffic
• providing 'port-a-loos' to suburbs with no sewage or water
• working on restoring electricity to homes and businesses
• closing all schools so buildings could be inspected.

The New Zealand Army was sent to the worst affected areas within Canterbury. Cordons were set up to protect people from falling debris near damaged buildings. All schools were closed so buildings could be inspected. International agencies also came to the aid of Christchurch.

Effects in Christchurch

Electricity to 75 per cent of the city was cut in the September quake. In February most of the city was without power. Most households had power within two to three days, but some regions took much longer. Several buildings caught fire after the earthquake.

Damage to buried pipes allowed sewage to contaminate the water supply so people had to boil their tap water. Beaches and waterways were polluted and closed to swimming for many months.

Christchurch airport was closed until runways had been checked.

Four hundred thousand tonnes of silt from liquefaction had to be removed from streets and properties.

Many of the most badly-affected structures in both Christchurch and the surrounding districts were older buildings with brick frontages, or buildings in areas where liquefaction occurred.  A fund was set up to try and repair damaged historic buildings.

Many roads were closed and traffic diverted, making it difficult to reach certain parts of the city. Businesses lost income as damaged buildings were closed. Customers found it difficult to get to certain shops due to cordons and road closures. Many businesses have had to relocate, some for the second time since the first earthquake back in September 2010.

Over 5000 properties were classified as being in the red zone, meaning the land was not suitable for building on. Over 10,000 homes needed to be demolished and rebuilt. Hundreds of buildings in the centre of the city have been demolished.

The disaster is estimated to cost insurers 10-20 billion dollars.

Liquefaction

(Pronounced “lick-wi-fack-shin”)

Liquefaction occurs when soil loses strength and stiffness due to earthquake shaking. Loose, sandy soils behave like a liquid as water is forced up to the surface.

Liquefaction affected large areas of Christchurch because many suburbs are built on soft soils or sand. Damage from liquefaction may have been worsened by the high water table from a wet winter.

Liquefaction caused:

• drains and pipes to float upwards, sometimes breaking through concrete paths and roads
• structural damage to buildings
• flooding
• sand volcanoes.

Read the Environment Canterbury (ECan) fact sheet on liquefaction to find out more (2Mb).

Schools 

One hundred and sixty three primary and secondary schools were affected by the earthquake, most of which were closed for three weeks. Ninety schools had full structural clearance and were able to reopen. Twenty four had reports indicating further assessment and 11 were seriously damaged. 

Due to the damage of a number of secondary schools, many were forced to share with others. One school used the ground in the morning and the other in the afternoon. Nine "learning hubs" were established throughout the city to provide resources and support for students needing to work from home. Some students relocated to other centres – by 5 March, a total of 4879 Christchurch students had enrolled in other schools across New Zealand. 

When 2 becomes 1

In September 2012, Minister of Education Hekia Parata announced plans to permanently close and/or merge a number of schools due to falling roll numbers and quake damage. 

One school that was created from this decision is Waitākiri School. Waitākiri School was created through the merger of Burwood and Windsor Schools. Both schools were affected by the 2010 and 2011 Christchurch earthquakes. Burwood was one of the hardest hit areas with over 50 per cent of the school zone designated "Red Zone" and a loss to the school roll in excess of 200 children.

The first year for the new school was 2014, but there were many challenges:

• There were two separate school sites
• Families and staff were still suffering the effects of the earthquake
• The new school was large – 800 pupils
• There were new ways of doing things for many
• Some staff jobs were uncertain
• Planning for the new school was very challenging
• There was higher than normal staff sickness
• Major roadworks in the surrounding area was taking place.

 Waitākiri School is where this field trip will be based.