The science behind the Quake NE of Culverden 14th November 2016

[JennyLeez]

Scientists investigating the mechanics of the earthquake say it faulted in the same way the February 22, 2011, Christchurch Earthquake did.

GNS Science seismologist John Ristau said the quake, which struck at magnitude 7.5 about 15 kilometres north-east of Culverden at 12.02am, was the result of what's called thrust faulting, a type of reverse faulting.

This was out of character for the area the quake struck in.

In reverse faulting, in a compressed area of the Earth's crust, one rocky block, called the "hanging-wall" block, is pushed up relative to rock, "the footwall block", on the other side.
This is the opposite to normal faulting, where the hanging-wall block moves downward and the crust is being pulled apart rather than compressed, and also different from "strike-slip" faulting, where two blocks slide sideways past each other.

The 7.1 Darfield earthquake in 2010 was a result of strike-slip faulting, 10km below the Canterbury town.

But the 6.3 aftershock that killed 185 people several months later was a thrust-faulting earthquake, occurring just 5km below Christchurch.

Its peak ground acceleration (PGA), the amount of acceleration of movement of the earth at the point recorded, reached 2.2g at the Christchurch epicentre, equivalent to the detonation of 15,000 tonnes of TNT.

Scientists are still calculating the PGA level at the Culverden epicentre of last night's quake, but the PGA in Wellington measured 0.23, similar to that of the 2013 Lake Grassmere and Cook Strait earthquakes.

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[TokWW]

Geonet are also recording a large landslide occured near Kaikoura of at least 1 million cubic metres of soil having moved.  At one fixed GPS station, reports are that it shifted north by 2metres.

[TonyC]

Cheviot had big earthquakes in 1901 and 1951, so I guess this one is a bit overdue.
This time it's spread somewhat wider.

[TokWW]

A link to support what I said earlier.  It was just hearsay before - off a twitter report but this is the link to the real statement.

http://www.stuff.co.nz/national/nz-earthquake/86429681/seismologists-record-2-metre-shift-south-of-marlborough

The title is misleading - yes the GPS unit was south of Blenheim (in Marlborough) and the land moved up to 2m north (6ft 6") and 1m sink for one GPS unit.  others were 600mm (2 feet) north movement.