Christchurch was shaken by a minor but widely felt earthquake on Saturday afternoon - the first quake felt by many in recent weeks.
GNS Science says the quake, which measured 3.9 on the Richter scale, occurred just before 3pm and was centred 10 kilometres west of Lyttelton, at a relatively shallow depth of five kilometres.
It was widely felt in the city, where people describe a rumbling followed by rattling.
There have been no reports of damage.
On Saturday morning a 5.5 quake shook Tuatapere in Southland.