Basically Auckland and the north part of the north island is the only part of the country not likely to be hit by an earthquake. But even then, Auckland is entirely built on volcanoes and Rangitoto Island in Auckland harbour or the volcanic field surrounding it might erupt and completely destroy the north island one day, although it hasn't erupted for about 700 years. And Northland might get swallowed by a tsunami.
So it's a reasonably safe and pleasant country to live in with nice weather (ironically Christchurch probably has the best climate), but there is some risk of natural disaster pretty much everywhere!
You forgot to mention Taupo - that's about a 2 hour drive from me - and Mt Ruapehu>
Ruapehu is one of the world's most active volcanoes and the largest active volcano in New Zealand. It is the highest point in the North Island and includes three major peaks: Tahurangi (2,797 m), Te Heuheu (2,755 m) and Paretetaitonga (2,751 m). The deep, active crater is between the peaks and fills with a crater lake between major eruptions. http://en.wikipedia.org/wiki/Mount_Ruapehu
It also where the 2 largest ski fields are in NZ
We, like you Alex, are not prepared one bit, though we do have a freezer full of meat and a BBQ.