Tsunami debris uncovered at KaikouraDAVID WILLIAMS Last updated 05:00 26/03/2012
Evidence of tsunami debris has been uncovered on the Kaikoura coast, prompting fresh calls for evacuation routes to be established and warning signs erected.
For years scientists have warned of a tsunami threat along that coast, with modelling work suggesting that waves more than 10 metres high could inundate the coast within minutes if a strong earthquake triggered a large underwater landslide.
The latest research, by Canterbury University doctoral student Jen DuBois, found evidence of a pebble-bearing layer in the ground that thinned inland and contained micro-fossils of freshwater and marine organisms.
Such deposits were not found further north or south of the 22-kilometre coast from Kaikoura's South Bay to Oaro, the area thought to be most at risk from a near-shore tsunami.
The Kaikoura Canyon comes to within 500m of the shore at Goose Bay.
A summary report of DuBois' thesis was sent last week to Environment Canterbury.
Her summary report said Kaikoura was "completely unprepared" for a near-shore tsunami.
"Signs with inundation mapping and evacuation routes need to be installed," she said.
ECan has formed a tsunami working group involving organisations such as the Kaikoura District Council, the Conservation Department, the NZ Transport Agency and KiwiRail. ECan has set aside $150,000 over the next three years for tsunami-related investigations.
Scientists from GNS Science and the National Institute of Water and Atmospheric Research are considering further mapping work in the Kaikoura Canyon.
ECan geological hazard analyst Helen Grant said the group wanted to raise the awareness of the tsunami risk through tourist operators and accommodation providers.
"We don't want to scare people off because the risk is no greater than it is along other parts of the eastern North Island and South Island."
Previous warnings about the tsunami risk have met resistance from some Kaikoura local body politicians and some sectors of the tourism industry.
Kaikoura District Council emergency management officer Don Clark, who had not read DuBois' report, said once suitable evacuation tracks had been identified, evacuation advice signs would be erected.
"I would like to see ... signs up within 12 months."
Research suggests a catastrophic tsunami could cause more than 100 deaths and cause more than $100 million damage to infrastructure and the local economy.
Waves more than 10m high hitting the coast are thought to be a worst-case scenario. It depends on the complete failure of a 200 million cubic metre slurry of silt, gravel and mud that has been washed into the sea by Canterbury rivers.
At least 16 tsunamis have had "some impact" since European occupation.
GNS Science natural hazards research manager Kelvin Berryman said there would not be a big impact on Christchurch from a Kaikoura Canyon slump.
Christchurch would have about an hour's warning and the waves would be about two metres above sea level
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They have been doing research there for some time I think as hear they were there some time ago.
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December 26, 2016, 10:20:53 AM