NIWA diverts ship to earthquake areas
NIWA’s flagship research vessel Tangaroa has been diverted to survey the seabed in areas affected by Monday’s earthquake.
Chief Executive John Morgan announced today that Tangaroa will be in the Cook Strait, Marlborough and Kaikoura regions from tomorrow morning and the survey would last up to five days.
“It is important to find out as soon as possible what has happened to the sea floor since this week’s earthquake. NIWA is happy to provide its expertise and leading-edge scientific equipment to build up a picture of what happened and what might have changed.”
Coincidentally, NIWA has several of New Zealand’s leading marine geologists on board Tangaroa at the moment, undertaking research on the Hikurangi subduction zone, off the North Island’s East Coast.
Looking for underwater landslides
Mr Morgan said the fact that marine geologists were already on board provided the perfect opportunity to respond quickly by carrying out coring and survey work in the earthquake-affected areas. They will undertake sediment coring off Kaikoura to identity any sediment flows as a result of submarine landslides. Each core can be up to six metres long and would have tell-tale geological signatures.
Voyage leader and NIWA marine geologist Dr Phil Barnes said the magnitude 7.8 earthquake early on Monday morning potentially triggered submarine landslides, and may have produced fault scarps on the continental shelf.
Cores will be collected from the southern Hikurangi region that may provide the opportunity to identify new sediment layers deposited into deeper water.
Complex quake features offshore
Scientists will also undertake multibeam surveys on the Marlborough coast in search of potential fault surface ruptures. Multibeam echosounders emit a fan of sound beams to the seafloor to scan a wide area of the seabed in detail.
A nearshore survey of the seafloor bathymetry will be undertaken off the Marlborough coast to search for fault breaks that may be visible on the seafloor.
Dr Barnes said the results will be compared with previous survey results to improve mapping of the faults, and to identify any changes. This offshore surveying is an important component of the geoscience response required to understand the complexity of this earthquake.
NIWA has previously undertaken rapid response measures after severe earthquakes, including conducting seabed surveys in Pegasus Bay, after the Christchurch 2011 earthquake and in Cook Strait after the Seddon earthquakes in 2013.
A briefing for media about the earthquake survey work is likely to take place next week.