Want to know the risks and latest natural disaster news in New Zealand. Perhaps the best website to visit is the one maintained by GeoNet.
There is a range of information you can obtain from this site. Perhaps the most important is:
1. The location of the most recent earthquakes - the pattern might give you a sense of the risk you are taking buying a house. The risk does not need to preclude buying a house, but simply managing the risk on a local scale, i.e. Avoiding sandy, low-lying flats subject to liquefaction, river plains subject to fault-induced flooding, cliff lines subject to collapse. You would want to make sure you are covered for earthquake damage if you are just about to buy a house in a 'quake-vulnerable' area.
2. The location of historical earthquakes - to give you an idea of what is possible.
3. List of earthquakes in your area - you can get a details picture of the earthquakes in the area you define, over the time period you define.
4. The characteristics of NZ quakes - this page will give you a basic overview of the nature of NZ earthquakes.
Volcanic eruption risk
There are also hazards posed by volcanic eruptions in NZ, so you will want to be aware of the risks posed by these. Eruptions can happen as frequently as every 10 years, or more typically every 300-400 years. Some volcanoes like Mauna Loa in Hawaii erupt every year and the eruption can continue for months. The only active volcanoes in NZ extend from Mt Ruepehu to White Island on the North Island. The volcanoes occur in the Taupo Volcanic Zone, which extends into the Bay of Plenty. For more information, refer to the following sources
1. List of NZ's active volcanoes. This page provides a geographic reference as well as information on the current level of volcanic activity. i.e. There is an alert level for different levels of activity. You can also correlate the level of localised earthquakes which often relate to movement of subterranean molten rock. i.e. Often an escalation of such activity is a precursor to a volcanic eruption.
2. The risks posed by volcanoes: Volcanic eruptions can eject water, rock and ask into the atmosphere, which can fall on nearby and distant regions. Most of the ash will fall down-wind on the days of the active emissions. The force and point of ejection will also matter. Some eruptions occur from a side vent, often due to a collapse of the volcano. e.g. Mt St Helens in the USA. The eruption of lava is less common, but a real risk. The greatest risk comes from volcaniclastic and lahar mudflows, as ash mixes with snow melt and the rainfall caused by ash clouds raising water droplet nucleation rates in the atmosphere, which encourages rainfall, flooding and mud-sponsors damage to settlement in river valleys. The ash cloud does not simply go up, but blows out from the flanks of the volcano in the direction of the eruption, and of course is influenced by the wind direction.
Tsunamis in NZ
I would be less concerned by tsunamis in NZ. The greatest risks are on the north and southern extremities of the archipelago, as well as the Pacific 'east' coast. The risk on the west coast is far low. There are tsunami warning stations in NZ. For more information refer to GeoNet. The risk posed is of course on the lowest-lying coastlines.
Earthquakes, high rainfall, frost-thaw and volcanic eruptions can cause rock falls or land slides. Be careful to avoid driving past such hazards in such times of active earthquakes. Rocks are more inclined to dislodge at night due to contraction. Rock falls which block rivers can also cause flooding, however the prospect of this is less of a threat.