An earthquake measuring 5.5 on the Richter scale hit the sea region off the Guam Island at 0539 GMT on Saturday, the U.S. Geological Survey said.
The epicenter, with a depth of 148 km, was initially determined to be at 13.991 degrees north latitude and 145.022 degrees east longitude, 65 km north northeast of Hagatna, Guam, Xinhua reported.