New Zealand tsunami risk

NZ: Risk of bigger tsunamis

A review of the risk posed by tsunami has found parts of New Zealand could be struck by waves 50% bigger than previously thought. It also says they could strike before official warnings were issued.

Radio NZ,
30 September, 2013

GNS Science says the changes to its predictions have been driven by research into the 2011 Japan tsunami, which indicates some fault lines near New Zealand could produce much larger earthquakes than previously thought.

The GNS review found a powerful earthquake on one of those fault lines could result in a 15m high tsunami striking Northland and Great Barrier Island, along with parts of the East Coast of the North Island and Wairarapa.

The wave could surge more than 30m above sea level on steep parts of the coast, a height comparable to the 2011 Japan tsunami.

The agency also included Southland and the West Coast as areas where fault lines could produce much larger earthquakes than previously thought.

Tsunami warnings could be too late

On top of that, a natural hazards researcher at GNS Science, Graham Leonard, says the wave could arrive less than an hour after the earthquake which generated it, and before official warnings could be broadcast.

Dr Leonard says that means people need to run for high ground as soon as they feel a strong quake.

People living on the coast need to know they should run for high ground if they feel a quake strong enough that they cannot stand, or which lasts for more than a minute.

Dr Leonard also says it's important people stay out of evacuation zones until they get the all clear from Civil Defence.

Civil Defence says it plans to discuss the findings with local councils and reinforce messages about the risk of tsunami to the public.