A 7.7-magnitude earthquake struck the Mariana Islands in the Pacific Ocean early Saturday.The quake occurred at a depth of 117 miles (212 km) some 19 miles south-southwest of the uninhabited island of Agrihan in the U.S. territory, the U.S. Geological Survey said.No tsunami warning has been issued, according to the National Tsunami Warning Center. Spokesman Paul Whitmore said a barely noticeable wave of about two inches was recorded in Saipan, the largest of the islands.The Commonwealth of the Northern Mariana Islands lies about 5,800 miles south-southwest of California’s Pacific shore.The quake was felt in the neighboring territory of Guam, with Twitter user @JRaemier telling CNN it woke her up and @Katfayeee saying it was the biggest earthquake she’d experienced.The USGS reported four smaller earthquakes in the Mariana Islands area over the next few hours. The next biggest measured 4.9 and occurred 7 miles (11 km) south of Agrihan at a depth of 122 miles.