An earthquake measuring 6.4 on the Richter scale jolted the sea region off Vanuatu at 0604 GMT Friday, the U.S. Geological Survey said.

The epicenter, with a depth of 35 km, was initially determined to be at 13.664 degrees south latitude and 166.409 degrees east longitude. It was 220 km north northwest of Espiritu Santo, Vanuatu.