Christchurch earthquake

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February 22nd Earthquake
On Tuesday 22nd of February 2011 there was a 6.3 magnitude earthquake at 12:51pm. The damage in Christchurch was far more substantial than the damage caused in the 7.1 earthquake only 5 months before. 185 people were killed in the February earth quake and thousands more were injured. The epicentre of the earthquake was very close to Lyttelton and only 10 kilometres out from Christchurch Central city. The fault line that ruptured and caused the earth quake was the 15 kilometre fault along the southern edge of the city from Cashmere to Avon Heathcoat estuary.

The build-up of stress or pressure in the rocks below Christchurch The earth is made up of many tectonic plates. It is the movement of these plates that has created the geographical features of many countries. New Zealand lies on the boundary between two of these plates: The Pacific Plate and the Australian Plate. This boundary is most obvious along the Southern Alps. From this main fault there are many smaller ones spreading outwards. Some of these spread into Canterbury. Before the 2010 and 2011 earthquakes it was not thought that there were any significant fault lines near Christchurch. Now we know there are. Stress is not caused by the movement of tectonic plates, but more by when the edges of the plates jam against each other and stop moving. The pressure builds up behind the part that has jammed. Eventually the pressure is so great that the plate moves suddenly and this causes earthquakes. The build-up of stress and the sudden movement when the stress is released shakes the rocks deep under Christchurch. The fault lines under and near the city shake, causing the rocks to move. This causes the major earthquakes.The outer core of the earth is layer of molten rock. On top of this is the mantle. On top of the mantle is the earth’s crust that we live on. The mantle gets very hot and in thin places molten rock rises to its top. Because of this hot and cold...
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