The New Zealand city of Christchurch was hit by an earthquake early today - four months after 181 people were killed by a 6.3-magnitude shock.
A magnitude 5.5 tremor rattled the quake-prone city at 1pm local time (0100GMT) today sending people fleeing from buildings, and boulders tumbling down hillsides, the Reuters newsagency reported.
Police said there were no initial reports of injuries.
The quake was located six miles south-east of the central city at a depth of 6.8 miles.
Aftershocks sent boulders on the city's Port Hills tumbling towards housing, while parts of the eastern city were flooded, it was reported.
Christchurch has experienced a number of strong earthquakes since a magnitude 7.1 quake struck the city on September 4 last year.
New Zealand records more than 14,000 earthquakes a year because it is on a blackspot for seismic activity.
The south-western Pacific country is on the boundary of two tectonic plates - and will always be vulnerable to natural disasters
New Zealand sits within a "ring of fire" - an arc of volcanic and earthquake zones taking in the south Pacific, eastern Indonesia, Japan and into Alaska.
These areas, because they are so close to plate boundaries, are more likely to be hit by quakes when plates start moving as the earth tries to release heat.