Authorities in New Zealand are evacuating residents from earthquake-hit Christchurch as Prime Minister John Key visited the city to assess the damage. Key travelled to Christchurch with Civil Defence Minister John Carter after the 7.0 magnitude earthquake rocked the country's second largest city early this morning. A state of emergency has been declared in the city and the Selwyn District, and the area was shaken by aftershocks. Building facades have collapsed, cars have been crushed and many homes have suffered damage in the quake. Water, power and sewerage are also affected and the airport is closed. No-one has been killed, but two people have been seriously injured and many others have also suffered some injuries, including broken bones and cuts.