A swarm of earthquake aftershocks hit mid-Canterbury overnight, with 10 recorded between 9pm on Thursday and 5am on Friday.
The tremors ranged in intensity from 3.1 to 4.4 on the Richter scale. Six occurred within less than an hour, between 10.28 and 11.23.
The 4.4 jolt, which hit just after midnight, was very shallow in seismological terms at a depth of only three kilometres.
It was centred 20 kilometres south-west of Darfield.
A 3.5 jolt was felt at 8.29am on Friday, followed by a 3.7 one at 10.59 and a 3.9 at 11.22.