10 Canterbury aftershocks since Thursday's 5.1

File photo / NZ Herald

Canterbury has been rattled by 10 aftershocks in the wake of a 5.1 magnitude quake that struck early yesterday morning.

The latest quake, a 3.8 magnitude jolt 20km south-east of Darfield, hit at 8.33am today.

It followed a 4.4 magnitude aftershock that struck at a depth of 7km, about 10kms south-west of Christchurch, at 2.12am.

GNS Science seismologist John Ristau said the quakes have been triggered by yesterday's 5.1 aftershock - one of the largest to hit Canterbury since the 7.1 magnitude earthquake on September 4 last year.

"They are aftershocks of an aftershock.

"An earthquake of that size is going to trigger its own small sequence of earthquakes."

Seismologists had no idea how long Canterbury's aftershocks would continue, he said.

"At the time [following the September 4 quake] we said it could be months or even a year. It would not be a surprise if we have fives every month for a while yet."

- NZHERALD STAFF