The Alpine Fault runs along the country’s South Island and it has a history of sudden movements.
Scientists can read the lakes and old-growth forests in the foothills of the Southern Alps and learn about what’s come before. What they have found reveals a great earthquake, one of the biggest in New Zealand’s modern history, is due.
In studying the Alpine Fault, scientists have created a timeline of its history and they know it makes very big shifts, on average, about every 300 years.
It’s complex science that dates the last magnitude-8 earthquake along the fault line to the year 1717. Simple maths tells us it’s been more than 300 years since then.
So, what kind of earthquake is next for the Alpine Fault? That’s the question senior lecturer in physical geography at the Victoria University of Wellington Jamie Howarth and his team recently set out to answer.
The team developed the richest record yet of the Alpine Fault’s history and found a pattern, one that helps them reliably forecast what’s to come. They gathered a whole lot of data from lake beds along the Alpine Fault – geological archives waiting to be read.
After an earthquake, there is an increase in erosion because the sediment from the earthquake-induced landslides is transported to the lakes. And evidence of that is stored away in the natural archive.
An earthquake might only last for a few minutes, but the geological impacts can persist for decades.
For more information, please visit: www.abc.net.au/news/2021-06-22/nz-racing-to-be-ready-for-magnitude-8-on-alpine-fault/100134024