18/06/2018

The potential threat posed to this region by the Hikurangi subduction zone – New Zealand’s largest boundary fault – is the subject of a major research project.

The Institute of Geological and Nuclear Science (GNS) is carrying out the research jointly with the National Institute of Water and Atmospheric Research (NIWA) and international agencies.

Subduction is where one tectonic plate dives or “subducts” beneath another. Subduction zones cause the world’s largest earthquakes and generate devastating tsunami.

While the Hikurangi subduction zone extends from the Cook Straight to beyond the East Cape, the research is focused here because it is very shallow beneath the coast. This makes it a globally unique place to determine shallow subduction process involved in earthquake and tsunami generation.
The research covers several areas including paleo seismic investigations at Pakarae and the installation of seismograph stations around the East Cape.

Researchers will investigate rock properties along the subduction interface to help determine what controls plate coupling and earthquake slip behaviour.

Also planned is an onshore seismic survey from the coast north of Gisborne to the Bay of Plenty over the 2018-19 summer. This will require drilling several approximately 50m deep seismic shot holes each of which will hold around 350kg of explosives.

During a presentation on the research to Council’s Assets and Infrastructure committee, Dr Stuart Henrys from GNS said the intention of this was to generate seismic waves from explosions and the energy that bounces back from the layers in the earth could also be recorded on seismographs.

Community consultation on this will begin in the coming weeks.

GNS and NIWA have received $6.47million from the Ministry of Business, Innovation and Enterprise to support the research.

Once complete, the findings will improve local earthquake simulation models. The information about Hikurangi margin earthquake sources will inform the pilot development of a real-time tsunami warning system.

ENDS

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