New Zealand's South Island was hit by two earthquakes of magnitude 6 or greater, the U.S. Geological Survey said on its Web site. There were no immediate reports of casualties or damage.

A magnitude-6 quake struck 95 kilometers (59 miles) west- northwest of Queenstown at 10:28 a.m. local time today at a depth of 39 kilometers, the USGS said. Another quake, of magnitude 6.8, struck about nine hours earlier, 103 kilometers west-northwest of Queenstown. That quake was 25 kilometers deep.

There were no reports of casualties or damage, a Queenstown police sapokesman said by telephone after the first quake.

New Zealand lies in a zone where the Indo-Australian and Pacific tectonic plates meet. Quakes occur as the plates push together and tremors of magnitude 5 and higher can cause damage depending on their depth.

There was no tsunami threat to coastlines along the Pacific Ocean, the U.S. government's Pacific Tsunami Warning Center said on its Web site after the bigger tremor. It added that local tsunami were possible within a few hundred kilometers of the quake. There were no reports of any.

A magnitude-7.4 quake struck near New Zealand's Auckland Islands on Sept. 30. The country has as many as 15,000 earthquakes a year and the biggest since instrumental recording began was a magnitude-7.8 temblor in 1931 in Hawke's Bay, according to the USGS Web site.