Taranaki Liquefaction Study About to Begin

A study to determine the risk of liquefaction in Taranaki after a severe earthquake will begin soon.

The region’s four councils as well as Powerco and Transpower are funding jointly the study by GNS Science. It will involve examining existing land data held by the councils in conjunction with geological information held by GNS to identify the potential for liquefaction and ground damage in the region.

NPDC Manager Quality Assurance John Sutton says the Christchurch earthquakes had shown the importance of knowing the liquefaction hazards as part of planning for emergencies and infrastructure – such as pipelines and electricity networks.

“We’re taking a region-wide approach as this information will be valuable for Taranaki Civil Defence Emergency Management and its preparedness for emergencies,” says Mr Sutton.

“As well, the councils will be able to see what the situation is in their local areas and plan accordingly, whether it’s for liquefaction or ground disturbance. This will be useful for land use management such as subdivisions and building requirements.”

The GNS Science report is due by the end of the year. It will include information on the geology of New Plymouth and the Taranaki region, the history of earthquakes and recorded liquefaction events in the region, known faulting and the estimated recurrence of shaking of sufficient strength to cause liquefaction, liquefaction and ground damage potential during a strong (MM intensity 7 to 10) earthquake, and mitigation options.

The New Zealand MM – or Modified Mercalli – intensity scale grades the impact of an earthquake on people, which can be more useful as an indicator of the earthquake’s significance to the community. More information on the MM intensity scale is available on GeoNet’s website.