2 hours ago
DateTime: Saturday May 5 2012, 23:33:13 UTC
Region: Cook Strait, New Zealand
Depth: 31 km
Source: CSEM-EMSC Feed
This ^^^^^^^^^^^^^^Wellington's tsunami risk.
HANK SCHOUTEN Last updated 05:00 19/03/2011
Tsunami generated by an earthquake in Cook Strait could sweep kilometres inland within three or four minutes, putting the lives of up to 170,000 Wellington residents at risk.
There would be no time for any warnings and people need to think now about how they can get to higher ground immediately after a strong quake, says Wellington Region Emergency Management officer Rian van Schalkwyk.
"The magnitude of that quake and tsunami in Japan is the sort of thing we can expect here. The moment there is a big local quake that is so strong that you can't stand upright, you need to get to higher ground or up in a building as quickly as possible. There is no time to hop in a car to drive away – just go up as quickly as possible.
"In Japan the quake was 200 kilometres offshore, but for us it could be 15km to 20km ..."
A tsunami caused by a quake that close "could be 15 metres high and it will come into the harbour and destroy everything in its path", he said.
The biggest threats were faults through Cook Strait and the Wairarapa coast and the possibility of huge landslides in the Cook Strait trench.
Mr van Schalkwyk said the tsunami triggered by the 8.2 magnitude quake on the Wairarapa Fault in 1855 was up to five metres high when it swept over Lyall Bay and Kilbirnie into Evans Bay.
A 10-metre wave struck Palliser Bay on the south Wairarapa coast. The tsunami also flooded Porirua Harbour, and hit Titahi Bay and the Kapiti Coast.
Mr van Schalkwyk said Greater Wellington regional council had drawn up maps showing evacuation zones for the most vulnerable areas. In the red, orange and yellow zones people need to be prepared to evacuate if there is a tsunami. The red zone is mainly for beach areas that could be hit by a one-metre tsunami generated thousands of kilometres away and during which people are advised to stay off the beaches.
The orange zone is based on a tsunami similar to that which happened in 1855, and the yellow zone is based on how far the devastation might extend if a 10-metre wave struck.
A tsunami of that size would threaten Wellington's commercial heart – the waterfront, the central business district and all the flat land as far south as the Basin Reserve, the suburbs of Island Bay, Lyall Bay, Kilbirnie, Miramar, Seatoun, Eastbourne, much of Lower Hutt, Titahi Bay, Porirua, Plimmerton, Paekakariki, Paraparaumu, Waikanae and Otaki.
[link to www.stuff.co.nz
Very interesting artical.