A massive earthquake fault running through New Zealand's south is overdue for a big shake that could block highways and leave thousands cut off, according to a new collection of research.
The "Alpine Fault" runs about 500km up the western side of the South Island and scientists say evidence shows over the past 8000 years it's produced a magnitude 8.1 rupture roughly every three centuries on average at fairly regular intervals
The last was in 1717 and rocked the area so hard it shifted its southern side by eight metres in a few seconds.
Now, marking that quake's 300th anniversary, a dozen papers have been published in a special edition of the New Zealand Journal of Geology and Geophysics looking at what the next big tremor could mean for the area.
"Whatever we can learn about this fault and how it moves will help us understand and prepare for the next great earthquake," chief guest editor Phaedra Upton said.
One of the studies included finds in the event of a magnitude 7.9 rupture along the fault, more than 120 parts of highways along the South Island could be left blocked, with about as many as 10,000 locals cut, and several thousands more tourists, cut off.
Restoring the road network could prove a "substantial" challenge, with some fixes possibly taking as long as six months to even begin, the report by Tom Robinson of Durham University said.
The research used the devastating 7.8 Kaikoura earthquake of 2016 as a guide to potential effects.
"Examining the response to the Kaikoura earthquake is a useful analogue to highlight valuable lessons that can help with planning," Dr Robinson said.
Civil Defence Minister Kris Faafoi told reporters on Tuesday significant funding had gone into researching the fault and preparing for the next quake.
"There has been quite a bit of planning to make sure we're ready for that," he said.