LEAD: Christchurch hit by 17 quakes in 18 hours

Jan 2, 2012, 7:49 GMT

Wellington - New Zealand's quake-ravaged city of Christchurch was rocked Monday by 17 earthquakes in 18 hours.

No serious damage was reported from the swarm, which included two shakes stronger than magnitude 5 and another six between magnitude 4 and 5. The City Council issued a statement asking the 'community to look after neighbours, friends and family and take care during this difficult time.' The South Island's largest city has been racked by quakes since September 2010, including one in February that killed 181 people.

The first tremor, measuring 3.9, hit at 1:27 am (1227 GMT Sunday), and the city kept shaking with a significant tremor of magnitude 4.8 just before 7 pm, the state GeoNet organization, which monitors quakes, reported.

A double shock 12 seconds apart with the biggest of magnitude 5.5 struck before dawn and triggered an automatic power shutoff to 10,000 homes, but electricity was restored by 8 am.

All the quakes were relatively shallow at depths of 8 to 20 kilometres and centred close to the city.

Mayor Bob Parker said the City Council was doing everything it could to ensure that key services remained operational.

'People just want a good night's sleep at the moment, and when you're having a whole night of it, it's very, very difficult to get some sleep,' Roger Sutton, head of the Canterbury Earthquake Recovery Authority, told Radio New Zealand.