KEY POINTS:
New Zealand recorded 26 earthquakes of magnitude 5 or greater during 2007.
And although two of these were over 6.5, last year statistically was an average year for earthquakes in the country, GNS Science seismologist Brian Ferris said
While most big earthquakes in 2007 were distant from populated
areas or too deep to cause harm, the big Gisborne shake on December 20 was close enough to cause significant damage.
The 6.8 magnitude earthquake, centred offshore 50km southeast of Gisborne at a depth of 40km, was the most damaging in New Zealand since the Edgecumbe quake in March, 1987.
Three buildings collapsed in Gisborne city, others suffered severe structural damage while electricity, gas, water supply and sewage reticulation were also disrupted.
Last night, nearly three weeks after the shake, Gisborne district Civil Defence officer Richard Steele said 13 buildings in the city's central business district still had danger notices posted on them meaning that significant structural work was required before they could be used or occupied again.
Another 50 buildings also require restoration work.
Mr Steele said all people displaced by the earthquake had returned to their homes and Gisborne's annual influx of up to 25,000 extra people over the Christmas-New Year period had been about normal.
The other major 2007 earthquake occurred on October 16 and was centred 60km west of Milford Sound at a depth of 24km. It measured 6.7.
This quake caused landslides in the Milford Sound area and minor to moderate property damage in the lower South Island. Several aftershocks, to a magnitude of 6.2, also caused damage.
A total of 504 earthquakes were reported via the Geonet website and Mr Ferris said while that is twice the average, many of the "extra" quakes were part of the ongoing Matata swarm in central Bay of Plenty.
Seismic activity near Matata continued in 2007 with about 1200 earthquakes at a depth of about 5km. Activity is said to be caused by spreading of the earth's crust in the region.
Parts of Auckland felt shallow earthquakes centred in the Hauraki Gulf, east of Orewa, on February 21, with the biggest at 4.5.
Meanwhile, the Ministry of Civil Defence and Emergency Management says it recorded 900 weather and geological events or emergencies in 2007.
"Clearly, nowhere in New Zealand is hazard-free," said ministry director John Hamilton.
He said 2007 was a year of earthquakes, severe weather, tornadoes, floods, a lahar and an eruption.
The spread of events gave an important message, with Northland hit by flooding and severe weather; Gisborne and the lower South Island shaken by earthquakes; Taranaki hit by tornadoes; part of Otago flooded, and Mt Ruapehu producing a lahar and an eruption.
Mr Hamilton says the challenge is to know what hazards different parts of the country face, and to know how to be prepared for them.
