New research into major multi-fault earthquakes 'critical' for New Zealand

New research into major earthquakes is "critical" for New Zealand to prevent future devastation, a leading scientist warns.

Dr Tim Stahl is overseeing the EQC-funded research at the University of Canterbury, trying to pinpoint where and how faults might set each other off. This creates what's called a 'major multi-fault earthquake', which is significantly stronger than a normal quake.

"Earthquakes that rupture across multiple faults don't just affect a bigger area, they also add to the amount of energy released, creating stronger quakes. So it's really important to understand more about multi-fault earthquakes," Dr Stahl says.

"When you're looking at why and where an earthquake might jump across faults, you're looking at factors like the distance between faults and whether a fault travels straight or on an angle.

"In New Zealand, however, we also want to be able to take into account how our rock types behave under seismic stress and what happens with faults that have been labelled 'inactive'."

So far the Kaikōura quake is the most complex multi-fault earthquake ever recorded. If it had only ruptured the first fault it would have been a magnitude 7 quake. But because it was the first of 20-odd other faults, it combined into a magnitude 7.8 earthquake - which is around 16 times stronger.

"We really need to get a better idea of where this could happen and the impact it could create on the ground surface, on infrastructure like water and electricity, and on buildings," Dr Stahl says.

"Better models mean that we can give better information on the likelihood and impact of future multi-fault earthquakes to emergency managers, councils, infrastructure providers and the public."

Dr Stahl says the project will focus on an area that has not had detailed investigation so far - between Waiau and Blenheim, where there are known faults that may rupture in future multi-fault earthquakes.