Research is being done on the Hikurangi subduction zone off the East Coast, the country's most active fault.
A slow slip event, which is a silent and slow-burning earthquake, is changing the shape of parts of the North Island.
Dr Laura Wallace of GNS Science says one is currently happening off the coast of Gisborne.
She says the movement is 10 to 20 centimetres, a few years of plate motion happening in a few weeks.
