29 Jul 2018

Is Dunedin at risk of an earthquake?

2:56 pm on 29 July 2018

Scientists have investigated Dunedin's active faults, creating a clearer picture of the city's earthquake risk.

Dunedin

Photo: Flickr/denisbin

New faults have been uncovered and one fault extends closer to the city than previously thought.

However, they have a low level of activity and do not change the overall hazard to the city, study leader Pilar Villamor said.

The city could experience an earthquake in line with the magnitude of the 2010 Darfield quake, which damaged masonry in Christchurch and caused widespread liquefaction.

"People [should] not get worried about this report," Dr Villamor said.

"This is science that needs to be out and needs to be known by the public. Take on board and learn the lessons that we saw in Christchurch and Kaikōura, and just get ready without being scared about it.

"Get your survival kits and hook your fridges to the walls, and all those things that are really quite easy to do."

The study was the first step in building a greater understanding of the earthquake risk to the city.

It followed a recommendation from the Canterbury Earthquakes Royal Commission for more research to paint a better picture of the quake risk faced by population centres, she said.

Dunedin was chosen for the initial study as already known active faults could potentially have extended under the city and it was a compact city where local scientists are already working on earthquake research.

Like Christchurch, Dunedin also had many heritage buildings.

Scientists probed the sub-surface around the city on land and off the coast using techniques including conventional geological studies, geophysical techniques, GPS, satellite imagery and seismometers.

"A better understanding of the presence of active faults beneath, and close to, our cities is important for land use planning, risk management, and emergency response activities," Dr Villamor said.

"The study has provided a baseline for Dunedin city that should be reviewed as new data becomes available, including GPS data from new sites set up as part of this study."

The study recommended further investigations into the faults around Dunedin take place, including studies on how active the faults were.