A series of aftershocks have been felt in the New Zealand city of Christchurch, but there are no reports of significant damage.
The first and most severe aftershock was 5.1-magnitude at a depth of 10 kilometres.
It occurred early this morning and was felt as far away as Dunedin and Greymouth.
Eight other aftershocks of lower magnitude followed.
GNS Science says residents should prepare for aftershocks of this intensity every four to six weeks for up to a year.
There have been 4,500 aftershocks since a 7.1-magnitude earthquake hit the city on September 4 last year.
The epicentre of that quake was 40 kilometres west of Christchurch at a depth of 10km.
