Rescue crews are digging through the rubble of a major earthquake that struck New Zealand Saturday, in the early morning hours (local time).
The earthquake was originally estimated at magnitude 7.4 on the Richter scale, but has been downgraded to 7.0.
The epicenter of the strong quake is estimated to be 4 miles southeast of Christchurch, New Zealand's second-largest city and home to some 350,000 residents.
The quake struck at 4:35 a.m. Saturday, local time (9:35 a.m., Friday, Pacific time). USGS reports the quake was 10 miles deep within the Earth's crust.
Civil Defense Officials have activated the Crisis Management Center to manage resources and to open lines of communication with relief agencies and the media. Rescue crews are on site, combing through the rubble in the business district of downtown Christchurch.
The town's airport has been closed and rail services across south island have been suspended.
"It is very important that you do not panic," said a New Zealand radio announcer after the quake. Residents of Christchurch were urged to remain calm and to check on the status of the elderely and others who might need immediate assistance.
Chistchurch Mayor Bob Parker told Radio New Zealand that "the damage is very, very significant," adding that detailed inspections will be necessary before residents can return to some severely damaged homes and commercial buildings.
Officials in Christchurch issued a statement reporting "substantial infrastructure damage" to municipal facilities in the town and surrounding areas.
There are reports of widespread power outtages throughout the region. The quake and several aftershocks were felt in Christchurch and throughout the South Island. Reports indicate the shaking was felt as far away as Wellington, New Zealand.
There have been no report of casualties from the earthquake, but area hospitals report treating dozens of minor injuries. Local officials credit the early hour of the quake for the lack of casualties and the minimal amount of serious injuries.
The USGS says there is no immediate danger that the quake will generate tsunamis.
