New Zealand warned of devastating ‘megathrust’ earthquakes

A TYPE of fault responsible for the most destructive earthquakes and tsunamis in the world prompts warning of earthquake 11,000 times as powerful as NZ’s Christchurch quake.

A New Zealand scientist has warned that a previously dormant fault could generate “megathrust” earthquakes of up to magnitude 9.0 in the Pacific country and trigger giant tsunamis.

“We need to think Japan 2011 basically, because if our whole plate boundary ruptured it would be a magnitude-9 earthquake,” geologist Ursula Cochran of the Earth and geoscience research company GNS Science, told the Marlborough Express in a report published on Monday.

The Hikurangi plate boundary, located off the East Coast of New Zealand’s North Island, is where the Pacific tectonic plate dives underneath the Australian tectonic plate.

The so-called subduction zone had been thought dormant before the 7.8 tremor near Kaikoura in November 2016.

“One thing about reflecting on from the Kaikoura earthquake is we don’t want people to think this is the big one,” Cochran said.

Subduction zones are a type of fault and are responsible for the most destructive earthquakes and tsunamis in the world, such as Sumatra in 2004, Chile in 2010, and Japan in 2011.

Earthquakes are measured on a logarithmic scale which means that while the magnitude 7.8 Kaikoura earthquake released 177 times as much energy as the magnitude 6.3 February Christchurch quake that killed 185 people in 2011, a 9.0 megathrust would be more than 11,000 times as powerful.

A team of international scientists is currently studying the Hikurangi plate boundary to find out what risk it poses to New Zealand.

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