Quake's energy could have powered Christchurch for a year

The energy unleashed in the Kaikoura earthquake was equivalent to what could power Christchurch for an entire year.

That's according to a Canterbury University physics PhD student who calculated the energy release of the November 14 quake and the combined energy of those that had preceded it since 2010.

John Holdaway's model showed that the earthquake's energy release was nearly half that of every quake since 2010 combined.

He sourced the data from the GeoNet database and then used a decades-old formula to relate the magnitudes of earthquakes and their aftershocks from each year to a total energy release.

"Basically, it just relates the magnitude of a very large quake to the approximate energy released - and then you can relate the energy of the aftershock to that main quake."

The November 14 quake appeared to dwarf the others, as a simple step up in magnitude equated to 32 times more energy.

"Just going up by 0.2 on that scale means there's about two times more energy."

By those calculations, even the September 2010 quake that struck near Darfield, Canterbury - a 7.1 magnitude event - produced three to four times less energy than this week's one.

Its energy was also much more greater than the 6.3 quake that killed 185 people in Christchurch on February 22, 2011 and released an amount of energy equivalent to that of 15,000 tonnes of TNT.

Holdaway estimated the 7.5 Kaikoura Earthquake created some 10 to 12 quadrillion joules of energy.

"If you translate that into something relatable, if you could harness the energy of the earthquake and use that to power the city of Christchurch, you could power Christchurch for an entire year based on that energy release."