An earthquake measuring 7.0 on the Richter scale rocked off the Pacific island nation of Vanuatu at 1819 GMT on Saturday (0219 Beijing Time on Sunday), the U.S. Geological Survey said.
The epicenter, with a depth of 2 km, was initially determined to be at 18.343 degrees south latitude and 168.156 degrees east longitude, about 68 kilometers south southwest of Port-Vila, capital of Vanuatu.
It occurred about one and a half hours after a 7.5-magnitude quake hit almost the same place.
No tsunami warning was issued for either of the two powerful quake.