Victoria University geophysicist Associate Professor Simon Lamb's recent study shows the constant slipping of one end of a gigantic, underwater mega-fault - caused the other end to have to break free.
He says when the end of the mega-fault breaks, it fractures lots of faults all over the place - which is what happened in Kaikoura.
Stephen Lamb says it's like bending a big sheet of glass, which breaks into lots of fragments when you break it.
He hopes they'll be able to bring greater earthquake forecasting techniques from this study in the next few years.