Scientists are setting out on a voyage to better understand the risk of earthquakes and tsunamis from New Zealand’s biggest and most active fault, the Hikurangi subduction zone.
They will drop 20 earthquake sensors, on loan from Dalhousie University in Canada, about 100 kilometres off the Wairarapa coast.
The sensors, worth about $100,000 each, will remain on the ocean floor, at a depth of about 4000 metres, for a year.
They will be placed on either side of the Hikurangi subduction zone, which is where the Pacific plate dives underneath the Australian plate.
The devices will record quakes. After a year they will be re-floated and the data analysed.
Scientists from GNS, Victoria University and Canada are involved in the project.
“These sensors are going to sit on the sea floor and they’re going to act kind of like a stethoscope, listening for any small signals that the subduction zone is producing,” said Emily Warren-Smith, a GNS seismologist.
The scientists are interested in what’s known as the “locked zone” of the Hikurangi plate boundary.
In the locked zone, the plates have been stuck for hundreds, even thousands of years, meaning the type of earthquake that could be triggered there would be big, sudden and capable of generating a tsunami.
There hasn’t been a large earthquake in the area in living memory and scientists are interested in the smaller ones which happen more frequently.
“We’re expecting to see 10 times more earthquakes on the locked zone than are currently reported,” said Martha Savage, a geophysics professor from Victoria University.
Public insurer EQC is contributing $80,000 towards the project.
“If we better understand the locked portion of the fault and the smaller earthquakes that occur, it will help us prepare for the impacts of a large earthquake and potential tsunami should the fault come unstuck,” said Natalie Balfour, head of research at EQC.
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