Video will play in Play now Don't auto playNever auto playMonday's devastating earthquake has been upgraded from 7.5 to 7.8 magnitude. The change means aftershocks may be larger in magnitude for a longer period of time. "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. "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. "We know from the Christchurch earthquakes, the likelihood of earthquakes greater than magnitude 5 decreases over time," Brownlee said.

Source: New Zealand Herald November 16, 2016 04:51 UTC