Scientists are reassuring Christchurch residents that there is no heightened risk of a volcanic eruption or large tsunami as the aftershocks to the February quake continue.
The Prime Minister's Science Advisory Committee says that even if a 7.1 earthquake struck offshore, the tsunami generated would likely only affect beach and estuary areas.
The committee says significant tsunamis are generally only generated by earthquakes larger than a magnitude of 7.5, and by a substantial vertical displacement of the sea floor.
It also says there is no risk of the Banks Peninsula volcanoes erupting. They last erupted just under six million years ago, the committee says, and there is no evidence of magma remaining beneath the peninsula.