2011 Christchurch Earthquake
On Tuesday 22 February 2011, 12:51pm local time, a 6.3 magnitude earthquake struck the Canterbury region of Christchurch, New Zealand. Large tremors travelled throughout Christchurch and surrounding cities. Christchurch being New Zealand’s second most populated city, there were many casualties caused by the earthquake. Killing 185 people, the 2011 Christchurch earthquake is recorded as the nation’s most deadliest national disaster. It has an X rating on the Mercalli scale, signifying that it was an intense earthquake. The earthquake was reportedly felt throughout the South Island and also felt in parts of the North Island such as the lower and central parts. Even though the earthquake itself lasted only for 10 seconds, the location of the earthquake and the large amount of people living in the area was the reason to why there was so much damage caused by the earthquake.
Geological Information about the 2011 Christchurch Earthquake:
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New Zealand lies in between the 2 tectonic plates- the Indo-Australian plate and the Pacific plate. Many of New Zealand’s earthquakes are caused by the tension created between the 2 plates when they rub against each other. Even though Christchurch is not situated between he Indo-Australian plate and the Pacific plate, it is located on a fracture in the Pacific plate. So how does an earthquake occur in a fracture in a plate? Well, the tension that comes from rubbing against 2 plates can be directed towards a fracture in either one of the 2 plates. The rubbing of this earthquake was caused by the subduction between the Indo-Australian plate and the pacific plate. This happens when the Pacific plate begins to descend beneath the Indo-Australian plate. The earthquake caused had high ground acceleration. Ground acceleration regards the speed in which the ground moves in an earthquake. High ground acceleration was also related to how shallow the earthquake was which meant it would have caused more damage than a deeper earthquake with a higher magnitude.
Information about Aftershocks related to the 2011 Christchurch Earthquake:
2011 Christchurch earthquake was probably an aftershock of the Christchurch earthquake which occurred on the 4th of September which had a magnitude of 7.1. GNS Science New Zealand stated that this earthquake was technically an aftershock of the 2010 Christchurch earthquake. The reason why many scientists suggest that the 2011 Christchurch was an earthquake on its own is that it occurred on a different fault line to the 2010 Christchurch earthquake. In the first week, the earthquake had generated more than 361 aftershocks the largest aftershock occurred only 2 hours after the main shock which had a magnitude of 5.9. Aftershocks related to this earthquake which occurred spanned over the course of a few hours later to approximately one year later.
Casualties that occurred from 2011 Christchurch Earthquake:
During this earthquake, 185 people had died. Along with a large number of casualties, there were several thousands who were injured, out of which 164 people had serious injuries. The majority, 115 people, died from the collapse of the six-storey Canterbury Television building. Another building collapse in which many people died was in the 4-storey Pyne Gould Cooperation. 18 casualties were from the cause of this building collapsing. The region where most people died was in the Central City of Christchurch, having 169 deaths and 16 people died in other parts of Christchurch. Along with human casualties, there were many animals who died during the earthquake and many of the animals who survived the initial quake, did not survive the aftermath because of the restriction to food and water resources. Animal welfare agencies such as SPCA helped evacuate animals and distribute animal food and veterinary supplies to families in need.
Severe Damage caused by the Earthquake:
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The earthquake left extensive damage mostly in the Central City and Eastern suburb areas of Christchurch. A reason to why there was so much damage done was because that the land, infrastructure and roads were still either damaged or weak due to the 2010 Christchurch earthquake which had a magnitude of 7.1. many building which were made of stone and brick were damaged. Approximately 100 000 buildings were damaged and around 10 000 buildings had to be demolished and re-built.
After the earthquake has occurred, scientists divided Christchurch into 4 different land zones. The white zone regarded the land which did not yet be inspected for damages. Where the land had no damage or very minimal damage and could be rebuilt on safely was called the green zone. Where the land had a little more damage done, it was called the orange zone. This land had to be carefully inspected before there would be any construction occurring. Where the land was severely damaged and had become very unstable was called the red zone. Construction in zone may be difficult.
The water, gas and sewage systems were heavily damaged. Many family’s who survived the earthquake used chemical and portable toilets for days, weeks and even months. Family’s also found access to water through water tanks and also used supplies sent from overseas. They depended on these supplies for days, weeks and even months.
During the earthquake, liquefaction occurred in many parts of Christchurch. Liquefaction occurs when the sturdiness and hardness of soil is decreased by the tremors released from an earthquake. Places in which liquefaction occurred in Christchurch, it would be hard to rebuild on the same land because the land has an uneven and unsteady surface.
Many Churches and Cathedrals such as The Cathedral of the Blessed Sacrament and the Oxford Terrace Baptist Church received a lot of damage due to the interior support structure being old and not tolerable to large earthquakes.
After the earthquake has occurred, scientists divided Christchurch into 4 different land zones. The white zone regarded the land which did not yet be inspected for damages. Where the land had no damage or very minimal damage and could be rebuilt on safely was called the green zone. Where the land had a little more damage done, it was called the orange zone. This land had to be carefully inspected before there would be any construction occurring. Where the land was severely damaged and had become very unstable was called the red zone. Construction in zone may be difficult.
The water, gas and sewage systems were heavily damaged. Many family’s who survived the earthquake used chemical and portable toilets for days, weeks and even months. Family’s also found access to water through water tanks and also used supplies sent from overseas. They depended on these supplies for days, weeks and even months.
During the earthquake, liquefaction occurred in many parts of Christchurch. Liquefaction occurs when the sturdiness and hardness of soil is decreased by the tremors released from an earthquake. Places in which liquefaction occurred in Christchurch, it would be hard to rebuild on the same land because the land has an uneven and unsteady surface.
Many Churches and Cathedrals such as The Cathedral of the Blessed Sacrament and the Oxford Terrace Baptist Church received a lot of damage due to the interior support structure being old and not tolerable to large earthquakes.
Economical Effects:
Insurance dealers first estimated the total cost to reconstruct Christchurch’s damaged society was NZ$15 billion. When the total cost for repairing was calculated in April 2013, the estimated cost was NZ$40 billion. It went down in the record books as New Zealand’s most costliest natural disaster. Christchurch had experienced many earthquakes for a year long but the one that occurred on the 22 of February 2011 was the most deadliest and the most costliest.
Article written by Jesmetha Baladevan
Article written by Jesmetha Baladevan