New research has found large faults off the West Coast capable of causing earthquakes of up to magnitude 7.8.
The National Institute of Water and Atmospheric Research on Friday released its findings of a two year project which mapped a 320km stretch of coastline from Hokitika to Farewell Spit.
Scientists found 10 active marine faults, including three new faults within 30km of land.
The faults run parallel with the coast and vary in length from 10km to 120km.
NIWA marine geologist Philip Barnes says the faults are capable of causing earthquakes from 6.4 to 7.8 in magnitude.
"However, the rates of activity on the faults are extremely low, we're not expecting earthquakes on individual faults at return times - or frequencies - of less than perhaps twenty odd thousand years."
He says scientists have no idea when the faults last ruptured.
Dr Barnes says the information will be used for further work on the seismic and tsunami hazards in the area.
The West Coast has been the location of two severe earthquakes - a magnitude 7.8 Murchison earthquake in 1929 and a magnitude 7.1 Inangahua earthquake in 1968.
