Wellington, Oct 16: Aftershocks rattled New Zealand's South Island today up to 10 hours after a magnitude 6.8 earthquake struck the area, New Zealand seismologists said.
Six aftershocks, the strongest measuring 6.2 on the Richter scale, followed the original shake, which was centred 60 kilometres (38 miles) west of the isolated tourist settlement of Milford Sound, off the south-west coast of the South Island.
The first quake was at a depth of 24 kilometres, but was felt widely throughout the bottom half of the South Island.
Seismologists said there were reports of some landslides in the remote area, but police said there had been no damage or injuries in populated areas.
The region was expected to continue to feel aftershocks for several weeks after such a large earthquake.
''Aftershocks occur as the earth's crust adjusts to stresses caused by the main shock. No two aftershock sequences are exactly the same,'' said Bryan Field of New Zealand's Geological and Nuclear Sciences agency in a statement.
New Zealand scientists record about 14,000 earthquakes a year, of which about 20 top 5.0 on the Richter scale.
The last fatal earthquake in the geologically active country, caught between the Pacific and Indo-Australian tectonic plates, was in 1968 when an earthquake measuring 7.1 on the Richter scale killed three people on the South Island's West Coast.