Sep 3, 2010, 22:26 GMT
Wellington - Christchurch, the biggest city in New Zealand's South Island, was extensively damaged early Saturday by a massive 7.4-magnitude earthquake that flattened buildings, ripped up roads and cut power, water and sewage connections.
Seismologists said the quake, which was centred 30 kilometres west of the city, was one of the biggest to hit a population centre in one of the world's most earthquake-prone countries in the last century.
They said it caused extensive damage because it was centred only 10 kilometres underground. They revised an earlier estimate that it was 33 kilometres deep.
Only two serious injuries were reported and officials said mass casualties were avoided because the quake struck at 4.35 am when most people were still asleep.
There were reports of serious damage at the port of Lyttelton, 12 kilometres from the city centre, but no tsunami warning was issued.
As aftershocks continued to shake the city of nearly 400,000, police closed the central business district - where roads were blocked by the fallen facades of office blocks - because of the threat of further collapses.
News reports said police were investigating reports of looting of wrecked shops and businesses.
Residents in the suburbs, many still in pyjamas, reportedly walked the streets in a daze, inspecting devastated houses that looked as though they had been bombed.
The Avon River overflowed its banks to cause floods in some suburbs as the quake struck.
Power was cut to three-quarters of the city and the entire Canterbury province, where more than 550,000 people live in mainly rural areas.
Emergency services were flooded with calls and police urged residents not to use mobile phones and to stay indoors.
The quake was felt hundreds of kilometres away and civil defence officials activated the national crisis management centre at parliament in the capital, Wellington.
Christchurch International Airport was closed and the South Island rail network was shut down pending inspections for damage.
The quake was felt widely across the South Island and in Wellington, at the southern tip of the North Island.
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