A major earthquake off Alaska with a preliminary magnitude of 7.2 has prompted a tsunami advisory for the state's southern peninsula.The tsunami advisory was downgraded from an initial tsunami warning Wednesday afternoon after the earthquake struck about 50 miles south of Sand Point,

A lightly populated stretch of Alaska’s southern coast was under a tsunami warning Wednesday after a strong earthquake was felt throughout the region, and officials in the Pacific Northwest were evaluating whether there was any threat to coastlines there.