Wednesday , May 12 2021

Our most complex destiny: Kaikōura two years later



Scientists are still gaining rich lessons from the Kaikōura Earthquake, two years after 7.8 jolt shaken the country with the equivalent energy release of 400 atomic bombs.

Geology geology GNS Science, Dr Rob Langridge, said the event, which was hit shortly after midnight on November 14, 2016, was one of the most complex earthquakes seen anywhere in the world.

This was due to the many shortcomings that dropped in just one event.

Over 20 defects were implemented – 14 of them breached violently to replace land by more than a meter.

This effect could not be more dramatic than along Fault Kekerengu Marlborough, where the land was offset by as much as 12m.

In some places the blame was visible with hoisting folds extending across the countryside – known as some like Wall of Waiau.

Another lesson was that this complex earthquake stretches from one region to another – the earthquake began on deficiencies in North Canterbury and jumped to the north, triggering the major shortcomings in the Marlborough region, "said Langridge.

"The breaches of the breach formed a complex network of impressive northeast defects linked to northern deficiencies, which had a different way of moving."

Broadly speaking, the event had stimulated scientists to consider the role of Plate the Pacific under Marlborough.

Previously, it was thought that this part of the plate was "full" full, or linked to the pastry, but now it seems to play a large seismic role in this part of the South Island.

Shortly after the event, Langridge and colleagues began to collect scientific data on block barriers, landslides, landslide dams, tsunami and smoothness to help the community and give advice to government and councils.

"After a considerable amount of data collection, we set out a series of scientific papers in a number of magazines overseas and local, so that the information gained was a permanent place," he said.

"At present, we are keen to understand some of these shortcomings in the past history of fault.

"So we have funding to go back to the failures of Papatea, Kekerengu, Hundalee, Humps and Leader and the coastal story, to understand how these shortcomings work in previous earthquake circles."

There was still a lot of work done across a range of scientific areas, ranging from seismology to GPS based geodesi.

In Marlborough's Kekerengu Fault, near Waiau, the land was erected in some places by 12m. Picture / Kate Pedley
In Marlborough's Kekerengu Fault, near Waiau, the land was erected in some places by 12m. Picture / Kate Pedley

During this summer, his team would excavate ditches across May Papatea to understand when he moved in the past and how much he has moved over thousands of years.

This blame released an incredible amount of dependence in the 2016 earthquake – scientists had recorded up to 9m of vertical movement and 6m of horizontal movement.

"This is really up on the world stage as a huge displacement on the land," said Langridge.

"Understanding how long it takes to build up this amount of stress is the key to unlock these defects."

What was less clear was when the next big earthquake could hit.

GeoNet recorded more than 20,000 shocks in the year following the earthquake, with a number of thousands more recorded since then.

However, only a fraction of those that exceeded 3.0 in size, and the number of back-ups continued to fall.

GeoNet's most recent earthquake shaking prospects – a statistical measure that were likely to work out – gave a 15 percent chance of 6.0 to 6.9 after-food within the next three months, with a 46 per cent chance of this happen sometime over a 12 month period.

Langridge saw the potential for future beans as a case of human timescales compared to geological ones.

"The way I look at it, we live along a plate boundary that accumulates around 4m of stress every century," he said.

"Remotely we talk about the mid-19th century Awatere and Wairarapa earthquakes breaking some of the important plain boundaries.

"We have now seen some of the other shortcomings in the heart of New Zealand that are about this earthquake.

"We have to be prepared to prepare individually and as a society about the potential for future earthquakes – they are part of" "makeup."


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