The Pacific islands of Vanuatu and New Caledonia were shaken by a magnitude-7.5 earthquake, less than two hours after a magnitude-6.4 temblor hit the area, the U.S. Geological Survey said.

The latest quake struck at 11:46 p.m. local time, about 89 kilometers (55 miles) south-southwest of Isangel in Vanuatu, and 174 kilometers northeast of Tadine in New Caledonia's Loyalty Islands, the USGS said today in a preliminary report on its Web site. The quake struck at a depth of 89 kilometers and there were no immediate warnings of a potential tsunami.

The earlier temblor struck at 10:13 p.m. local time about 97 kilometers southwest of Isangel and 167 kilometers north- northeast of Tadine.