Queenstown should be prepared for post-quake situation worse than Kaikoura
Queenstown's isolation, mountainous terrain, dense population and proximity to the Alpine Fault means should an earthquake occur similar to Monday's magnitude 7.5, the situation would be worse than Kaikoura post-quake, experts say.
Emergency Management Otago and Otago Regional Council chairman Stephen Woodhead said now was the time to warn people of what was possible.
"Have a look at what has occurred [in Kaikoura]. This is not a good time to be blase. We know the Alpine Fault is due. We can't afford to be blase.
"I don't want to scare people but you just need to understand the nature of this."
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With just two road accesses into the resort winding through gorges and bluffs and "just about everything you can think of" with regard to hazards, the town could be cut off for weeks, Woodhead said.
"There's significant risk in Queenstown being cut off. The road access does have hazards attached with it. The Nevis Bluff [on State Highway 6] for example. The Nevis falls down on a sunny day [so] . . . we're not just talking small landslides. It will take quite some time to clear."
The risk of a tsunami was also very real, and plans were in place should this occur in Lake Wakatipu or Milford Sound, Woodhead said.
"You would have to be very, very quick to get out."
The number of visitors to Queenstown, especially during Christmas and Easter, could make it difficult logistically, Woodhead said.
Queenstown had about 1.6 million visitors per year, which equated to about 4500 per day on top of the 20,000 resident population. That made using helicopters to take between 14 and 20 people out at a time – as has been done in Kaikoura – a slow process, he said.
"Kiwi's tend to be quite resilient but . . . our communities aren't as resilient as years ago. We tend to have a 'just in time' society. Supermarkets and fuel tend to run out quite quickly.
"It's just a good opportunity for the Queenstown Lakes District and the whole community to say 'oh, this could happen here and are we prepared?"'
Otago Civil Defence emergency management officer for Central Otago Trevor Andrews said Queenstown would end up like Kaikoura but "tenfold really".
Businesses and the tourism sector in Queenstown needed to have emergency management plans in place, he said.
"Isolation is a given. We know that. Then it's thinking what we're going to do in here.
"If anything keeps me awake at night in this part of the country, it's how we will manage our guests and foreign nationals."
Tailored response plans for every community in the district were being worked on by Civil Defence groups with about 25 per cent of the work complete. Communities were expected to have completed plans within two years.
GNS principal scientist Kelvin Berryman said there was a 30 to 50 per cent chance of a large earthquake on the Alpine Fault in the next 50 years.
"With the potential consequences, I think everybody is in agreement that this is something to take seriously."
With the energy of Monday's earthquake heading north, Berryman believed the risk of a rupture on Alpine Fault had not been heightened.
Last month, emergency management conference attendees in Queenstown were told of the potential impact of a rupture of the Alpine Fault being like "Christchurch on steroids".