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International research to gather more information about NZ’s largest fault - 05/10/2018

An international team of scientists sets off this weekend to place earthquake monitoring instruments along New Zealand’s largest fault, the Hikurangi subduction zone.

An international team of scientists and engineers preparing highly specialized instruments to be deployed on the seafloor offshore the North Island's east coast. (from left), Pete LIljegren (Columbia University), Laura Wallace (GNS Science), Neville Palmer (GNS Science), Carlos Becerril (Columbia University), Spahr Webb (Columbia University), Yusuke Yamashita (Kyoto University), and Ted Koczynski (Columbia University). Photo – Margaret Low, GNS Science.

An international team of scientists and engineers preparing highly specialized instruments to be deployed on the seafloor offshore the North Island's east coast. (from left), Pete LIljegren (Columbia University), Laura Wallace (GNS Science), Neville Palmer (GNS Science), Carlos Becerril (Columbia University), Spahr Webb (Columbia University), Yusuke Yamashita (Kyoto University), and Ted Koczynski (Columbia University). Photo – Margaret Low, GNS Science.

About 40 instruments will record seismic movement and information that will help us better understand the earthquake and tsunami potential for the zone, which runs along the North Island’s East Coast.
 
“What we can learn about this fault and how it moves will help us understand and prepare for the next great earthquake,” GNS Science expedition leader Dr Daniel Barker says.
 
Subduction zones are where most of the world’s deadliest earthquakes, volcanoes and tsunamis occur, such as the Sumatra (2004) and northern Japan (2011) Magnitude 9 earthquakes and tsunami.
 
GNS Science is leading the operation aboard NIWA’s research ship R/V Tangaroa, and the instruments will be placed off the coast of Gisborne, Hawke’s Bay, and Wairarapa.
 
“This plate boundary has the potential to produce powerful earthquakes and tsunamis, so this research is a priority for New Zealand geoscientists,” project leader Dr Laura Wallace says.
 

Ocean Bottom Seismometers are prepared at GNS Science before being lowered to the seafloor to monitor earthquakes on the Hikurangi subduction zone.  Photo credit: Aliki Weststrate, GNS Science/Outer Reaches

Ocean Bottom Seismometers are prepared at GNS Science before being lowered to the seafloor to monitor earthquakes on the Hikurangi subduction zone. Photo credit: Aliki Weststrate, GNS Science/Outer Reaches

One of the instrument types being used are seafloor pressure sensors, that will record the upward or downward movement of the seabed. These can detect “slow motion earthquakes” offshore, and may also provide evidence about how the zone might behave in a large earthquake.
 
The team will also deploy two arrays of precision seafloor transponders to track horizontal movement of the seafloor, and several ocean bottom seismometers.
“We expect that the instruments will record many hundreds of small earthquakes that cannot be accurately located with land-based instruments,” Dr Wallace says.

 

The expedition includes scientists from GNS Science, Victoria University of Wellington, Lamont Doherty Earth Observatory (US), Scripps Institution of Oceanography (US), as well as Tohoku, Kyoto and Tokyo Universities in Japan.
 
“Because so many interesting things are occurring on the Hikurangi subduction zone, New Zealand provides an ideal natural laboratory to deploy these instruments”, said Professor Spahr Webb of Columbia University.