Warning over threat from giant megathrust quake
An 8.4 magnitude quake off the East Coast of New Zealand could release 2000 times more energy than the 2011 Christchurch earthquake, experts say.
It could cause a ‘‘megathrust’’ earthquake, and the dangers it poses were being discussed at a summit in Napier last week – with local councils, iwi and civil defence involved.
The potential risk comes from the Hikurangi subduction zone, a massive fault line running from Marlborough and right past the East Coast where the Pacific and Australian tectonic plates collide.
It is potentially the largest source of earthquake and tsunami hazards in New Zealand, but scientists say there is still much to learn about it.
GNS Scientist Dr Laura Wallace told TVNZ ‘‘it’s a massive plate boundary fault and subduction zones. Because they’re so large [they] have the potential to produce the world’s largest earthquake and tsunamis’’.
Marcus Hayes-Jones from Napier Civil Defence said he ‘‘can’t emphasise how serious’’ New Zealand must take this ‘‘genuine risk’’.
In 2015, scientists finally found proof that central New Zealand could be ticking down to a highly damaging ‘‘megathrust’’ earthquake.
Previous research has shown the Hikurangi-southern Kermadec subduction zone segment had the characteristics of the locations of previous giant earthquakes.
In a giant earthquake a very large part of a fault slips.
In the Boxing Day 2004 quake off Sumatra, which caused a tsunami that killed more than 200,000 people, about 1300 kilometres of the subduction zone fault slipped.
The Hikurangi subduction zone is part of a larger subduction zone called the HikurangiKermadec-Tonga subduction zone which stretchs all the way to Tonga.