GNS Science has revised the magnitude of the large earthquake that struck at 12:02am on Monday from a 7.5 to a 7.8, Acting Civil Defence Minister Gerry Brownlee says.
“GNS Science informed my office of the revised magnitude earlier today after reassessing the data from its stations across the country,” Mr Brownlee says.
“Because it took over a minute for the fault to rupture during this event, the standard method normally used to calculate the energy released during an earthquake was insufficient.
“The revised magnitude just tells us what anyone who felt the earthquake would already know – that it was a powerful tremor that lasted for a long time.
“It does not change what happened or how central government or local authorities responded. It simply provides us with more knowledge about how significant this earthquake was.
“As expected with a larger earthquake, the revised magnitude does have an effect on the probabilities of forecast aftershocks, meaning it is now forecast that aftershocks may be larger in magnitude for a longer period of time.