Strong Earthquake, Gisborne

A strong earthquake struck off the coast near Gisborne on the East Coast of New Zealand’s North Island last evening. There are some injuries, but no fatalities have been reported. Three buildings have collapsed but fires were quickly brought under control and damage to infrastructure such as roads, water and gas mains is reported.

A magnitude 6.8 earthquake struck off-shore 50 km south-east of Gisborne (ca 90 km north-east of Napier) on the evening of Thursday December 20th 2007. The 40 km-deep quake, which struck at 8:55 p.m., was located under the Pacific Ocean to the east of the North Island in the Pacific Plate which is sliding under the North Island at this location.

Initial reports indicate that two commercial buildings and one apartment building in the business area of Gisborne city have collapsed, water and gas mains have been damaged and some roads have sustained minor damage. However, the 10 or so fires that broke out were quickly brought under control, and power was restored to many areas within 2 hours of the tremor.

Damage to windows is reported, and many residents report that the contents of shelves and cupboards were thrown to the floor. Heavy furniture items such as freezers and fridges were moved by the quake. As many as 10 people may have been injured, but the extent of these injuries is not reported and no fatalities had been reported by 1 a.m. local time Friday morning.

Cook Hospital has sustained structural damage and, despite losing power for a time immediately after the quake, has continued operating. The centre of Gisborne has been cordoned off to maintain security and safety until daylight hours.

Whilst power has been restored to most parts of the network in the area, some residents are still without power due to localised faults caused by lines breaking or clashing during the shaking. Telephone service is operating but again some residents have lost service where individual lines have sustained damage.

Immediately after the earthquake, many residents in low-lying areas evacuated to higher ground fearing a tsunami wave. No sizeable wave has been reported following the quake. At this early stage, reports of damage are still awaited from more remote locations on the East Coast.

GeoNet’s website had received over 1200 reports of the quake by just after midnight, and MM8 shaking was reported from Wairoa which is located to the south of Gisborne. Reports from Gisborne and the city’s suburb of Whataupoko which sit on soft alluvial soils, indicate MM7 shaking, during which people have difficulty standing, furniture is shifted and weak buildings are damaged.

22 reports of slightly damaging shaking have been reported from the Bay of Plenty, Mahia Peninsula and Hawke’s Bay.

The earthquake was felt as far north as Auckland and in Taranaki. It was also felt along the West Coast of the South Island and as far south as Alexandra and Dunedin.

The Pacific Tsunami Warning Centre did not issue a bulletin for this event.

In March 1966 a smaller, shallower 6th magnitude earthquake struck just off Poverty Bay and caused considerable damage. A magnitude 6.3 quake struck inland from Gisborne, near Ormond, in 1993 and caused moderate damage.

[Compiled from local sources and data provided by the Geonet project and its sponsors EQC, GNS Science and FRST; and the US Geological Survey and its contributing agencies.]

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