Kaikoura's raised seabed an opportunity to see geology in action

Monday's earthquake raised parts of the Kaikoura by more than a metre, providing a unique insight for scientists.
Dr Joshu Mountjoy, a marine geologist at the National Institute of Water and Atmospheric Research (NIWA), said the seabed lift was a first for modern New Zealand Scientists.
"I've never seen it before during an earthquake and it's the first time we've seen something like this," Mountjoy said.

TREVOR BURKHART

Ward beach, where the seabed has risen 1.8 metres.

Co-seismic movement, the seismic release of energy along a fault, was behind the phenomenon, he said.

Mountjoy said historical examples of co-seismic movement could be seen all along New Zealand's east coast.

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One example of seabed raising was the 1931 Napier earthquake, which changed the shape of the Hawkes bay coastline.
While it would "take a while to understand exactly which faults have controlled which parts of the coastline", Mountjoy believed the Hundalee fault was responsible for uplifting part of the coastline.
"Some faults go side-to-side while others move vertically, like in this case, where the fault has pushed the land up into the air, and it appears to be by about a metre," Mountjoy said.

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The impact of the quakes effects will remain unknown until a survey of the seabed is carried out.

"This happens periodically in our young land. We get used to the situation as it is, and then this happens, so it will take a while before this becomes normal again."
One of the best examples of co-seismic movement on New Zealand's east coast was Turakirae Head south of Wellington.
"[The ridges] reflect individual earthquake events along the Wairarapa fault, and you can track a number of them back in time."

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Mike Vincent is calling for help as he tries to save thousands of paua after the seabed was shifted in Monday's earthquake.

Mountjoy said Monday's earthquake was a "very complex fault rupture" which affected multiple regions and resulted in "significant landscape change".
"It's not just a single rupture on one fault plain, it's ruptured multiple fault strands all along the coast there.
"So that uplift will reflect that behaviour of different faults."

TREVOR BURKHART

Burkhart Fisheries co-owner Trevor Burkhart removes paua from the elevated rocks at Ward Beach in Southern Malborough

http://i.stuff.co.nz/national/nz-earthquake/86528148/raised-seabed-off-kaikoura-coast-baffles-marine-experts