 Earthquakes are unpredictable and can occur at any time.  There is at least one earthquake that occurs somewhere in the world each day. Some can be slight tremors that can hardly be felt, while others can be much stronger.  Earthquakes happen because the Earth’s tectonic plates are always moving and floating on molten rock. An earthquake can last from a few seconds to a few minutes, which can be followed by after- shocks and can cause major devastation.

 The February 2011 Christchurch earthquake was a powerful natural event that severely damaged New Zealand's second-largest city, killing 185 people in one of the nation's deadliest peacetime disasters.  The magnitude 6.3 earthquake struck the Canterbury region in New Zealand's South Island at 12:51 pm on Tuesday, 22 February The earthquake was centred 2 kilometres west of the town of Lyttelton, and 10 kilometres (6 mi) south- east of the centre of Christchurch, New Zealand's second-most populous city.

The earthquake caused widespread damage across Christchurch, especially in the central city and eastern suburbs, with damage exacerbated by buildings and infrastructure already being weakened by the 4 September 2010 earthquake and its aftershocks. Significant liquefaction affected the eastern suburbs, producing around 400,000 tonnes of silt. The earthquake was reported to be felt across the South Island and the lower and central North Island.

Discuss the liquefaction in this picture:

In total, 185 people were killed in the earthquake, making it the second-deadliest natural disaster recorded in New Zealand (after the 1931 Hawke's Bay earthquake), and fourth-deadliest disaster of any kind recorded in New Zealand, with nationals from more than 20 countries among the victims. Over half of the deaths occurred in the six-storey Canterbury Television (CTV) Building, which collapsed and caught fire in the quake. The government declared a state of national emergency, which stayed in force until 30 April 2011.

The total cost to insurers of rebuilding has been estimated at NZ$15 billion, making it by far New Zealand's costliest natural disaster, and the third- costliest earthquake worldwide. The earthquake was the most damaging in a year-long earthquake swarm affecting the Christchurch area. It was followed by a large aftershock on 13 June (which caused considerable additional damage) and a series of large shocks on 23 December 2011.

Watch the BTN earthquake Japan. Discuss what it might like to be a kid in Japan during and after the earthquake and tsunami.

Create a list of things affected by earthquakes…