Christchurch, New Zealand

At 12:51pm on Tuesday, February 22nd, 2011 disaster struck 10 Kilometers South-East of Christchurch, the 2nd most populated city in New Zealand causing destruction throughout the city. Following the 6.3 magnitude earthquake many countries and organizations leaped into action by sending humanitarian aid and rescue workers into the region to help the destroyed area. Many buildings already had been weakened by the September 4, 2010 earthquake that measured 7.1 magnitudes on the Richter scale. One of the buildings destroyed was the Christchurch cathedral one of the oldest churches in New Zealand, the building had already been weakened by the September earthquake and the spire collapsed. A lot of the church was damaged. It is not known if the church can be rebuilt on the present site because of structural damage. Altogether the quake produced 181 fatalities and about 2000 injuries. As a result this earthquake is the second-deadliest Natural disaster in New Zealand history. An estimation of the cost to rebuild damaged areas is about U.S. $11.5-12 Billion dollars making it one of the costliest natural disaster in New Zealand history. From February 22nd, 2011 to April 30th, 2011 the New Zealand government declared the situation a state of national emergency. 

The Earthquake and Aftershocks

This 6.3 magnitude earthquake is considered an aftershock of the 7.1 magnitude quake that struck the Canterbury region in September 2010. New Zealand GNS Science called it "Technically an aftershock" but other seismologists consider it a different event because of the 2011 quake occurring on a different series of fault lines. This quake had a strike-slip motion and most of the buildings destroyed were pre-1970s designs like the Christchurch cathedral. Because of the building code of New Zealand larger loss of life was limited, although the most severe shaking lasted only 12 seconds which may have prevented more damage. The February quake produced many aftershocks for an earthquake of its size with about 361 aftershocks within the first week, the largest of all measured 5.9 and occurred just under 2 hours of the initial shock. One of the most resent happened on the morning of June 6th and measured 5.5 magnitudes. Even though the quake was a smaller magnitude than the September 2010 quake it was more deadly for a number of reasons. First, the epicentre of this earthquake was much closer to Christchurch (10km) whereas the September 7.1 magnitude was 40 km west of Christchurch. The 2011 quake was shallower in only 5 km underground, while the 2010 quake happened 10 km underground. Also many of the buildings had already been weakened by the 2010 earthquake. About 200'000 tonnes of silt lifted by the quake strongly affected the eastern suburbs of Christchurch. There was also surface flooding and soil liquefaction. Nearly 1000 buildings in central Christchurch are expected to be demolished due to the quake.