Natural Hazardscape: a summary of the natural hazards we faced in summer 2002/03

When it comes to earthquakes, the December–February quarter was a little quieter in 2002/03 than it was in the previous year, according to a report released today by the Natural Hazards Centre. There were 91 earthquakes of magnitude four and above, compared with 119 in the same period in 2001/2002.

Earthquakes of magnitude five and above can cause significant damage to buildings, and even injuries and deaths. This summer, there were seven such earthquakes. On 26 January 2003, a magnitude 5.6 earthquake centred 20 kilometres north of Pongaroa at a depth of 34 kilometres knocked goods off supermarket shelves in Woodville and Palmerston North. Other earthquakes of magnitude 5 or greater were located offshore, deep underground, or in isolated rural areas, so there was little reported damage.

A study linking the risk of house damage from earthquakes in New Zealand confirms that Wellington has by far the greatest risk.

“Almost all earthquake disasters that could cause more than $1.5 billion damage to domestic housing in New Zealand will happen in the Wellington area”, said Dr Terry Webb from the National Centre.

The seasonal summary from the Natural Hazards Centre records earthquake and volcanic activity, floods and droughts, extreme weather events, coastal hazards, and landslides. These natural hazards are recorded on maps of New Zealand in the quarterly newsletter Natural Hazards Update to graphically illustrate where and when they occurred.

Extreme natural hazard events in summer 2002/03:

• magnitude 5.6 earthquake centred north of Pongaroa at a depth of 34 kilometres knocked goods off supermarket shelves in Woodville and Palmerston North;
• severe drought in much of the east coast and central New Zealand;
• wind gusts of up to 150 km/h in December in the south of both the North and South Islands;
• highest February temperature for 50 years in Paraparaumu (29.6 °C);
• lowest ever February temperature in Christchurch (1.5 °C);
• snow fall on Boxing Day at the Homer tunnel;
• storm over northern New Zealand (26–27 February) caused floods at Paeroa with several houses evacuated, winds gusting up to 135 km/h in the outer Hauraki Gulf whipping up 8-metre waves, and an enforced 3-day lull in the America’s Cup final.

Natural Hazards Update publishes a quarterly review by the Natural Hazards Centre of such hazards in New Zealand, as well as other news and information on upcoming events.

The Centre is a joint initiative between the Institute of Geological and Nuclear Science (GNS) and the National Institute of Water & Atmospheric Research (NIWA), and was established to strengthen the links between scientists, policy makers, planners, and emergency managers.

The key role of the Centre is to communicate research results, and the aim is to ensure that research on hazards helps communities improve their resilience to natural hazards and better manage the risks they face.