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Focus AUV Fine scale Observations following earthquake-triggered Canyon flUShing by AUV survey

Project: FOCUS-AUV - Fine Scale Observations following earthquake-triggered Canyon flUShing by AUV survey

Scientific Discipline: Geology, Marine Biology, Sedimentology

Work Area: Kaikōura canyon, off the east coast of the South Island in New Zealand

Equipment: University of Gothenburg's AUV Ran and RV Tangaroa

Cruise Leader: Dr Joshu Mountjoy, National Institute of Water and Atmospheric Research (NIWA)

Dates: September 30 to October 29 2020

The FOCUS AUV Cruise took place in October 2020 on board the National Institute of Water and Atmospheric Research's (NIWA) RV Tangaroa with the University of Gothenburg's Hugin AUV Ran over 29 days. The AUV was used to survey the Kaikōura canyon, off the east coast of the South Island in New Zealand, to measure the ecological and sedimentological impact and recovery following the 2016 Kaikōura Earthquake.

Voyage leader and NIWA marine geologist Dr Joshu Mountjoy says this is the first time such a sophisticated piece of technology has operated in New Zealand waters and information collected will lead to new understanding relevant to many of the world’s continental margins.

Principle Investigator Dr Joshu Mountjoy and the AUV Ran

Following the earthquake in 2016 two NIWA surveys discovered large areas of the Kaikōura Canyon had drastically changed. An enormous amount of mud and sediment – estimated to be about 850 million metric tonnes – was shaken off the canyon rim and then flowed down into the canyon channel causing a powerful “flushing” of sediment out to the deep ocean.

The Survey Area

The principle aim of the cruise and use of the AUV was to understand the physical process that has removed such a huge amount of sediment and rock from the canyon. This flushing immediately turned the canyon from a biodiversity hotspot full of dense populations of large invertebrates and abundant fish species into a barren, almost uninhabited landscape.

A total of 14 dives were completed out of 17 planned dives. The survey areas had to be modified to allow for weather conditions, however the final overall operations and survey coverage are considered highly successful.

Vessel Track

Check out the cruise video below

Credits:

Photo in Heading - Tom Szumski, Marine Institute. Cruise Photos & video - NIWA