KEY POINTS:
Why are we asking this now?
Because New Zealand has been hit with a string of earthquakes in the past week.
The biggest - a 7.4 magnitude earthquake on Sunday - was felt in Stewart Island, Invercargill and Dunedin. It hit about 6.23pm near the Auckland Island.
Earlier
that day earthquakes measuring more than 4 on the Richter scale came within a minute of each other near Matata.
And last month Mt Ruapehu erupted without warning. William Pike, 22, an Auckland primary school teacher had his left leg crushed by a rock during the eruption and had to be rescued from the Dome Shelter near the crater.
The eruption was accompanied by a seven minute earthquake, measuring 2.9 on the Richter scale.
Why the Shaky Isles?
The Shaky Isles is a nickname for New Zealand, derived from the country's frequent seismic activity.
The North, South and Stewart Islands lie on the margin of two colliding tectonic plates, the Pacific and Indo-Australian Plates.
Their first meeting about 135 million years ago is what thrust the New Zealand landmass out of the ocean on the east coast of Gondwanaland.
The plates continue to push and slide against each other, periodically jolting different parts of the country and sending shudders through land and people, particularly in the southwest of the South Island and in the central North Island.
The North Island is marked by several active and dormant volcanic cones like Mt Ruapehu.
In the South Island the colliding plates have forced up the high, snow-capped range of mountains, the Southern Alps, which are rising about 1cm a year, just enough to compensate for the erosion in this high rainfall environment.
Some people believe a massive earthquake that hit near Wellington in 1855 sparked New Zealand's reputation as the Shaky Isles.
The quake, measuring 8.2 on the Richter scale, occurred on the Wairarapa fault line and lifted the eastern edge of the Rimutaka and Tararua Ranges by up to six metres.
It was said to have pushed the ranges about 12 metres north of previously adjoining points on the east.
It caused a tsunami that swept over what is now Wellington Airport and into shops along Lambton Quay, killing about six people.
Two others were reportedly killed in the Manawatu.
The phrase Shaky Isles is often used humorously by our counterparts in other countries, such as Australia.
Shaky Isles has been used as the title for songs referring to New Zealand - by Mike Harding in 1989 and Dave Dobbyn in 1991.
Following the Wellington earthquake these are some of the notable jolts New Zealand has experienced:
* In June 1929 a quake shook the small town of Murchison, near Nelson, killing 17 people. Bridges collapsed, roads were washed out and numerous buildings were damaged. Experts said if the earthquake had occurred in a more populated area it could have been New Zealand's biggest natural disaster.
* In 1931, an earthquake measuring 7.9 on the Richter scale rocked the Hawkes Bay and killed 256 people. Many buildings collapsed and stringent building codes were introduced to resist quakes more effectively.
Sailors from the New Zealand Navy who happened to be in the harbour at the time of the earthquake, helped with the clean-up. The experience of the Napier clean-up eventually led to the establishment of the NZ Civil Defence Organisation.
* In June 1942, an earthquake measuring 7 centred on Masterton and the Wairarapa shook the southern half of the North Island. Damage to Wellington's CBD led to a rethink in the way buildings were designed - many decorative gables, chimneys and towers were removed.
* And four people were killed in the May 1968 earthquake in Inungahua, near Buller. These are the last recorded earthquake fatalities in New Zealand.
* The most destructive in recent history was the 6.7 Edgecumbe quake in the Bay of Plenty in 1987, which caused $311 million of claims.
