HAGATNA, Guam - An undersea earthquake off Guam with a preliminary magnitude of 6.7 shook the U.S. territory Saturday morning, the U.S. Geological Survey said.

There were no reports of damage or injuries. A magnitude-6 earthquake can cause severe damage.

The quake failed to generate any destructive, widespread tsunami, according to the Pacific Tsunami Warning Center in Honolulu.

The quake struck at 7:51 a.m. at a depth of 54.4 miles, the survey said in a statement. It was centered 125 miles west-southwest of Hagatna, Guam, and 250 miles southwest of Saipan in the neighboring Northern Mariana Islands, it said.

Kim Alba, lifestyle editor at the Pacific Daily News, said that the quake jolted her house and woke her up, but that the shaking was apparently the extent of its impact on the island.

Air Force Tech Sgt. Brian Bahret, spokesman for Guam's Andersen Air Force Base, said there were no reports of damage there. And Sarrah Iguel, a dispatch operator for Civil Defense in the Marianas, said no one called to report damage.

Guam is west of the international date line, about 3,700 miles southwest of Hawaii.