Seismologist says supermoon could have triggered the north Canterbury earthquakes

The supermoon could have well have played a part in causing this morning's earthquakes (Getty)
The supermoon could have well have played a part in causing this morning's earthquakes (Getty)

Tonight, the moon will be at its closest point to the Earth in 68 years.

It might seem like the stuff of science fiction, but did this so-called 'supermoon' have anything to do with the powerful earthquakes that rocked New Zealand this morning?

Seismologist for GNS Science Dr John Ristau says it's entirely plausible the supermoon could be a factor.

"When you get the tidal forces from the moon it does cause increased stresses in the Earth's crust, so what can happen, potentially, is if you did have a fault that was almost at the very tipping point of rupturing, this could potentially act as the straw that broke the camel's back."

Looking at previous supermoons and possible connections to other major earthquakes, there was a supermoon on March 19 2011, eight days after the massive earthquake and tsunami that hit Japan.

On February 22 that year, Christchurch of course suffered a devastating quake in which 185 people died.

Like the previously unknown fault that ruptured under Christchurch in 2011, Dr Ristau says the one in north Canterbury is also unknown, and could have been near its tipping point.

"If you had a fault that was right there and was just about to break, all it needs is just one tiny little push. So that tiny little push, it could coincidentally happen at the time when there's a full moon, when the tidal forces are high."

Strangle lights were also seen the skies last night. The lights appeared exactly when the quake occurred and were filmed in Wellington:

Strange lights were also seen in the skies above Canterbury during the 7.1 magnitude quake centred on Darfield in 2010.

Dr Ristau says there is a simple explanation.

"When you have a fault, and as the stresses are building up in the fault, you actually have fluids that are in the rocks. These fluids almost act like a plasma; it's like a charged liquid.

"As the stresses build up it releases magnetic energy up into the air, and it almost acts like lightning, expect coming from the ground."

GNS now says the 7.5 magnitude earthquake was actually two separate events.

"The initial earthquake was around Kaikoura, and it was a reverse fault type quake - that's when one side of the ground lifts up over the other," says Dr Ristau.

"But then, after that it continued, and it likely initiated the second earthquake offshore that was a strike slip, which is a side-type motion.

"What we don't know for sure yet is what the relative strength of these two earthquakes were, if they were roughly the same size or if one was quite a bit bigger than the other."

Dr Ristau says people living in the affected areas should prepare for hundreds of aftershocks within the next few weeks, or even months.