Scientists from the National Institute of Water and Atmospheric Research have found no active faults after their preliminary research off the coast of Christchurch.
The scientists have been working on the research vessel Kaharoa in parts of Pegasus Bay, in the area near Sumner and Banks Peninsula.
Voyage leader Dr Philip Barnes says initial testing of up to 100 metres of the sea-floor shows no sign of faults.
He says the scientists have started using a second device that monitors to a depth of 2 kilometres - but those results won't be available for about three months.
Mr Barnes says his team will return to Wellington on Thursday to start collating the latest data.