NIWA Summer Series – Kaikoura Canyon Post Earthquake

By Guest Author 20/12/2017

In January and February several NIWA scientists focused on finding out more about what happened to marine environment off Kaikoura following the November 2016 earthquake. Marine geologist Dr Josh Mountjoy led an investigation to map offshore faults ruptured by the earthquake and to investigate changes at the head of the Kaikoura Canyon.

Data revealed huge mudslides had occurred sending mud and debris in the canyon’s central channel. Dr Mountjoy said the amount of debris that cascaded through the canyon was massive.

“Some individual landslides are more than three times the size of the landslides that damaged the road to the north of Kaikōura.”

A second survey led by NIWA marine ecologist Dr Dave Bowden used cameras to survey the seafloor further into the arm of the canyon tp see if the damage to a renowned biodiversity hotspot.They found while the structure of the canyon had remained intact, the mudslides had left no evidence of seabed life.

But in September the scientists went back and found signs of recovery in the seabed with evidence that juveniles of animals that once dominated the head of the canyon have now begun colonising the seafloor.

“The deep-sea communities might be recovering faster than we originally thought, with high densities of small organisms such as urchins and sea cucumbers in some areas of the canyon, as well as large numbers of rattail fishes swimming immediately above the seabed.”

Image: NIWA marine geologist Dr Joshu Mountjoy conducts a seabed survey off the Kaikoura coast following the earthquake. [Photo: Dave Allen, NIWA]

This article was originally published on NIWA, as part of their Summer Series 2017