Natural Hazards in New Zealand

As with any country, if you are considering where to live, it helps to have an idea of what natural hazards pose a risk to your new lifestyle. Here is a quick summary.

EARTHQUAKE
New Zealand is known as "The shaky isles" and is located on the Pacific "ring of fire". Major fault lines run the length of the country, and small localised faults may also cause damaging quakes. In the North Island, the high-risk zone includes Wellington, Wairarapa and the entire East Coast (Hawkes bay and Gisborne). Northland and Auckland are comparitively low-risk and the rest of the island is moderate risk. Bay of Plenty and the Central plateau have also been noted for having swarms of small earthquakes in recent years.
In the South Island the high rish areas are Fiordland, Westland, Buller and Marlborough. Canterbury has a fairly high risk due to the size of the possible quake across on the Alpine fault and the soft nature of soils. Eastern Southland is the only low-risk area in the south. There have been about a dozen quakes of Magnitude 7 or greater since European settlement, but many were in remote and sparsely settled areas. Only two have had a death toll higher than 10, the worst being the 1931 quake in Napier where 231 people lost their lives. Since then, New Zealand's building standards have been extensively revised and New Zealand is a world leader in Earthquake engineering research.

VOLCANOES
New Zealand has four active volcanoes and numerous dormant and extinct ones. Auckland is built on a field of small volcanic cones, the most recent being Rangitoto island (1750). The existing cones never re-erupt, but a new volcano could take out a couple of suburbs.

In the central North Island, Ruapehu, Tongariro and Ngaruahoe erupt periodically. Ruapehu's 1992 ash eruption basically disrupted the ski season and air travel. There is now extensive monitoring for the risk of lahars (mud flows) down rivers, and an event in 2008 was spectacular but largely uneventful due to warnings.

The Taranaki landscape is dominated by Mt Taranaki, which has entirely rebuilt its spectacular 2,500m cone after a cone collapse 3,000 years ago. It's last eruption was 250 years ago and it is probably due to do something, with a higher possibility of it occurring on the south side.

TORNADOES
Most of the estimated 30 tornadoes which touch down in New Zealand each year happen in the west of the country, and mostly in remote areas where no one even sees them. The tornadoes tend to be small and brief (class 1-2) Taranaki has the highest risk and urban areas were struck by two twisters in 2007, miraculously with minimal injuries.

HURRICANES
In the South Pacific, Hurricanes and Typhoons are known as Tropical Cyclones - more correctly as Extra-Tropical Cyclones by the time they reach New Zealand, which might be once every year or so. Northland, the Coromandel Peninsula, Bay of Plenty and Gisborne are most regularly affected, and although most are relatively low grade, they can occasionally wreak considerable damage, mostly through torrential rainfall. Cyclone Bola in 1981 was the worst in recent memory.

FLOODING
New Zealand is a mountainous country, so much of the best farmland is in river valleys, as are a number of towns. Flood protection works abound, but every now and then they are breached by a larger-than-predicted flood. Christchurch is at risk from the Waimakariri river, which has historically had a very mobile mouth. The local museum of any town usually has good documentation of historical floods.

LANDSLIPS
To avoid the river flats you can buy on the hills. But with the loss of forest cover, erosion can be a problem. Check the past history of the district. New Zealand has a number of key roads through river gorges, and many of these are prone to landslips during heavy rain. These quite often lead to a road closure, but it is very rare for a vehicle to be hit by one. Don't stop to admire the scenery, though!

TSUNAMI
A large number of New Zealanders live on the coastline. Tsunami risk is highest on the east coast and in the north. There have been no damaging tsunami since European settlement.
BLIZZARD
Livestock are at greatest risk from blizzards, but if you are in the south in winter and the radio mentions a "polar blast", be careful on the road or stay put somewhere warm and comfy. Snow doesn't hang around at low levels for long periods in New Zealand.

PROTECTION
The state body EQC (www.eqc.govt.nz) insures against damage caused by earthquake, natural landslip, volcanic eruption, hydrothermal activity, tsunami; in the case of residential land, a storm or flood; or fire caused by any of these. It is funded by a levy on all house insurance. Note that cover is usually based on the value of your house, not the land it sits on.