Submerged landslide in study

Grant funds three-year project off Poverty Bay

Grant funds three-year project off Poverty Bay

UNDERSEA SLIP: A 3D image of the Tuaheni landslide complex off the coast of Gisborne. Image supplied by Niwa

THE tsunami risk posed by an ancient but ongoing landslide submerged off the Poverty Bay coast will be the centre of a new international study.

The Marsden Fund yesterday announced a $850,000 grant to allow cutting-edge laboratory experiments on sediment samples taken from the Tuaheni landslide complex to be carried out to determine how the landslides respond to gas pressure build-up and earthquake motions.

Niwa marine biologist Joshu Mountjoy said the main driver for the three-year project was to understand how landslides moved under water.

“Big landslides like this are the size of Auckland city but we still don’t fully understand if they move catastrophically and really fast, or if they are slowly creeping along — and that makes a huge difference to whether they will cause a tsunami.”

The project would start in the new year and would bring together previous research including 3D imaging of the landslide and drill samples taken from the landslide, which is located about 40km south east of Gisborne.

“Bringing those together and testing the samples will allow us to understand how the landslide is moving.”

Dr Mountjoy said it was thought that contrary to most other examples, the Tuaheni landslide was moving slowly. The project would also allow the international team of researchers, including scientists from New Zealand and Germany, to date material taken from the landslide.

“We believe it’s all within the last 20,000 years but some parts of it are still moving today so its virtually a modern system — that’s our hypothesis.”

Research teams led by Dr Mountjoy and Dr Gareth Crutchley from GNS Science would use resulting data to model various scenarios by which landslides are initiated to help to determine the tsunami hazard potential of such features.

The Marsden Fund is administered by the Royal Society of New Zealand on behalf of the Ministry of Business, Innovation and Employment.

THE tsunami risk posed by an ancient but ongoing landslide submerged off the Poverty Bay coast will be the centre of a new international study.

The Marsden Fund yesterday announced a $850,000 grant to allow cutting-edge laboratory experiments on sediment samples taken from the Tuaheni landslide complex to be carried out to determine how the landslides respond to gas pressure build-up and earthquake motions.

Niwa marine biologist Joshu Mountjoy said the main driver for the three-year project was to understand how landslides moved under water.

“Big landslides like this are the size of Auckland city but we still don’t fully understand if they move catastrophically and really fast, or if they are slowly creeping along — and that makes a huge difference to whether they will cause a tsunami.”

The project would start in the new year and would bring together previous research including 3D imaging of the landslide and drill samples taken from the landslide, which is located about 40km south east of Gisborne.

“Bringing those together and testing the samples will allow us to understand how the landslide is moving.”

Dr Mountjoy said it was thought that contrary to most other examples, the Tuaheni landslide was moving slowly. The project would also allow the international team of researchers, including scientists from New Zealand and Germany, to date material taken from the landslide.

“We believe it’s all within the last 20,000 years but some parts of it are still moving today so its virtually a modern system — that’s our hypothesis.”

Research teams led by Dr Mountjoy and Dr Gareth Crutchley from GNS Science would use resulting data to model various scenarios by which landslides are initiated to help to determine the tsunami hazard potential of such features.

The Marsden Fund is administered by the Royal Society of New Zealand on behalf of the Ministry of Business, Innovation and Employment.

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