A magnitude 4.9 earthquake was felt in Canterbury on Friday morning.
The quake at about 3.29am was centred 10km east of Lyttelton, at a depth of 6km.
There have been no reports of damage.
Seismologist Brian Ferris says the quake was felt strongly throughout Canterbury and further south in Timaru.
Police say they have had no calls related to the quake so far and there are no reports of damage or power cuts.
A magnitude 2.8 quake occurred within 5km of Lyttelton at 11.56pm on Thursday. It was at a depth of 8km.
On Sunday, 4 September it will be a year since a magnitude 7.1 earthquake hit Christchurch at 4.35am, causing widespread damage.
