Tsunami risk zone huge

22:15, May 18 2014
The view from Mount Victoria in Devonport
IN THE ZONE: The view from Mount Victoria in Devonport, looking out over towards Auckland city.

Thousands of homes and businesses in Auckland have been included in tsunami evacuation zones drawn up by Auckland Council.

The zones , some of which extend inland for more than a kilometre from the coast, cover parts of the city's industrial heartland as well as some of its most expensive residential suburbs, and would need to be evacuated immediately if there was a serious earthquake in the undersea Kermadec-Tonga subduction zone to the east of the Auckland region.

The council says anyone within the zones should leave immediately if they feel a weak rolling earthquake that lasts for more than one minute, or an earthquake of any duration that is strong enough to make it difficult to stand up.

If such an earthquake was to occur, a tsunami could arrive within minutes or up to an hour after the quake, the council warnings state.

"The only credible scenario for that to happen in Auckland is if we have a large rupture on the Tonga-Kermadec trench, which lies 300 kilometres east of Auckland," said Richard Woods, the hazard adviser for the Auckland Council's civil defence and emergency management department.

"Everyone would feel that earthquake and the evacuation areas identify the maximum area that would be affected by inundation from that event," he said.


In the CBD, the tsunami zone extends up Queen St as far as Victoria St, including the lower half of Shortland St, all of Fort St, Customs St and Quay St, and all of the port, Viaduct Harbour and Westhaven. The zone also extends part way up College Hill to the west of the CBD and virtually all the way up Stanley St to the east.

On the city's exposed northern coast, huge numbers of homes and businesses would need to be evacuated.

At Orewa, the zone extends back more than two kilometres from the beach, and at Milford it extends more than a kilometre from the coast, and includes all of its commercial strip.

Devonport would also be badly affected and all of the homes located between Mt Victoria and North Head extending all the way to Cheltenham Beach would need to be evacuated.

Central city suburbs such as Herne Bay and Westmere would also be affected, with the tsunami zone extending as far inland as the lower reaches of Richmond Rd, while to the east, large tracts of Kohimarama, Mission Bay and St Heliers would need to be evacuated.

Several major commercial property precincts are also located within the evacuation areas.

Two major shopping malls, Pakuranga Plaza and the Milford Centre, are within the tsunami zones.

Industrial properties are also affected, with all of Barry's Point Rd and Fred Thomas Drive on the North Shore, some of the industrial areas in New Lynn and parts of the industrial hub of East Tamaki, including the northern quarter of Highbrook Business Park which is owned by Goodman Property Trust, included within the tsunami zones.

However most property owners appear to be in the dark about the existence of the zones, or the need to evacuate their premises in the event of an earthquake if they are located within them.

Kim Bennett, the chief executive of Ladstone Holdings which owns the Pakuranga Plaza shopping mall, was unaware it was included in a tsunami zone.

"We haven't been told," he said.

"The council has been talking to us about the unitary plan and Pakuranga Town Centre Plan and every other thing, but not about that.

"As an operator of shopping centres, we need to have plans [for possible evacuation]", he said.

John Dakin, the chief executive of Goodman Property Trust, which owns several commercial properties at Highbrook within the tsunami zone, said the company became aware of the issue only because one of its staff members was involved with Civil Defence.

"We have not been specifically advised by the council of the new tsunami mapping," he said.

"However, one of our staff members has made enquiries through her involvement with Civil Defence and the council will be providing us with a briefing shortly.

"While I suspect the risk is minimal, we will review our existing procedures in light of the new mapping."

Auckland Council's Civil Defence Controller Clive Manley said it would be left to local community groups to decide how to make people in their area aware of the zones.

Some cities had marked the boundaries of tsunami zones with street signs and even lines painted on roads to make people aware of them, but Manley said the council would not require such steps to be taken.

"We have what we call community response groups, who could be half a dozen or a dozen people who have been nominated or elected by their communities, who work with us on how that community would plan [for a disaster]," Manley said.

"It's an informal group in the sense that they are usually part of other groups like Rotary or churches, so we tap into those networks."

Auckland Property Investors

Association president David Whitburn believes the council should be identifying properties within the tsunami zones on their LIM (Land Information Memorandum) reports, which are supposed to list all natural hazards.

However Woods said the information would not be appearing on LIMs, because their contents were governed by statute, which did not require it.

Although the council has posted maps on its website which identify all of the tsunami zones in the region, people may need to make a determined effort to find them.

"Just Googling and searching the Auckland Council website, I can't even find them," Whitburn said.

Hayden Duncan, the chief executive of the Harcourts real estate group, said he didn't think the zones would affect property prices or where people chose to live in the city.

"Most of Auckland is within a few minutes of the coastline and we are surrounded by water. I don't think we necessarily need to start looking at the what ifs," he said.

"Those people that are concerned about it will investigate, but I don't think most Aucklanders would give too many moments thought to it." he said.

People who want to check whether a property in the Auckland region is located within one of the tsunami evacuation zones, should check out the maps at www.aucklandcivildefence.org.nz/community/tsunami-evacuation-maps/

Sunday Star Times