GNS Science has lowered the magnitude of an aftershock which struck Christchurch this morning from 4.6 to 4.2.
The 5.14am tremor was centred 10km south east of Christchurch at a depth of 8km, GNS Science said.
It was felt in Christchurch.
Meanwhile, a 3.4 magnitude tremor struck in the same area at 8.04am.
The quake was 7km deep and centred 10km south west of Christchurch, GNS said.
