Understanding the Hikurangi subduction zone

Hawke’s Bay mayors, councillors, council staff, taiwhenua representatives and Civil Defence staff from throughout New Zealand will have the opportunity to find out the most up to date information on the Hikurangi subduction zone off the East Coast this week.

Geophyscist Dr Laura Wallace is one of several leading scientists taking part in a two day short course run by GNS Science and hosted by East Coast LAB today and tomorrow at the National Aquarium of New Zealand in Napier.

The Hikurangi subduction zone runs along the northeast coast of the South Island and along the East Coast of the North Island. The subduction zone is capable of generating a magnitude 8.5 earthquake that, in addition to widespread ground shaking, is also likely to produce a tsunami, coastal uplift and subsidence, landslides and liquefaction. 

The course presents state-of-the-art knowledge of Hikurangi subduction zone hazards in New Zealand, and will help those attending to better understand how their organisation can prepare for, and mitigate against a future earthquake and tsunami crisis. 

Dr Laura Wallace says the Hikurangi subduction zone has attracted a huge amount of international interest as a globally significant natural laboratory to investigate subduction plate boundary processes.

“What makes subduction zones rupture in huge, tsunami-generating earthquakes is one of the most pressing questions facing scientists today and been the subject of a lot of research in recent years,” says Dr Wallace.

Along with outlining what they know so far, the scientists will also discuss a number of future research projects in the Hikurangi subduction zone including:

• pre-historic earthquake studies and seismic surveys to understand the causes and consequences of subduction earthquakes at the Hikurangi margin;
• deployments of seafloor instrumentation over the next five years to investigate the current plate movements at our offshore plate boundary;
• the world’s first scientific drilling project targeted at understanding the origins of slow slip events where installing a permanent observatory inside two of the drillholes to monitor any offshore changes due to slow slip events, earthquakes, and tsunamis;
• a 3D seismic survey in early 2018 offshore Gisborne to image the source of slow slip events at unprecedented resolution.

East Coast LAB Project chairperson Lisa Pearse says it is great to see such a massive international and national investment in trying to understand the Hikurangi plate boundary.

“The more we understand about the plate boundary, the better prepared we can be,” says Lisa Pearse.

She says East Coast LAB will be sharing the research with schools and communites right along the East Coast so they understand the risks of living life at the plate boundary. 

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