Hazards
As well as the direct effects of explosions, lava, and pyroclastic flows, volcanoes pose various hazards to the New Zealand populace. These include tsunamis, breakout floods and lahars from volcanically dammed lakes, ashfall, and other far field effects.
For instance, the Tangiwai disaster occurred on 24 December 1953 when the Tangiwai railway bridge across the Whangaehu River collapsed from a lahar in full flood, just before an express train was about to cross it. The train could not stop in time, and 151 lives were lost. This was ultimately caused by Ruapehu's 1945 eruption, which had emptied the crater lake and dammed the outlet with tephra.
Effects can be widespread even for eruptions of only moderate size. Ash plumes from Ruapehu's 1996 eruption forced the closure of eleven airports, including Auckland International Airport.
Insurance against volcanic damage (along with other natural disasters) is provided by the country's Earthquake Commission.
Read more about this topic: Volcanology Of New Zealand