Tsunami warnings along the Pacific coasts of the United States and Canada were cancelled Tuesday after a major early-morning earthquake struck off the coast of Alaska. The 7.9-magnitude earthquake struck shortly after midnight in the Gulf of Alaska, 280 kilometers southeast of the town of Kodiak, the U.S. Geological Survey (USGS) said, revising lower a preliminary estimate of 8.2-magnitude. The epicenter was 10 kilometers under the seafloor. The National Tsunami Warning Center confirmed a tsunami, meaning the ocean levels were above normal. Waves of 30 centimeters were detected in parts of southern Alaska, authorities said, and as a precaution, officials in the areas encouraged residents to remain on higher ground. But the monitoring center later cancelled warnings and watches for coastal regions in the U.S. state of Alaska, Canada's British Colombia province, and the U.S. west coast "because additional information and analysis have better defined the threat." There were no immediate reports of injury or damage along the Alaska coast or on Kodiak Island. Residents in Anchorage, Alaska, about 580 kilometers away from the epicenter, said the city shook for a long time. The USGS said the earthquake occurred "as the result of strike slip faulting," explaining that it was in a location where two tectonic plates converged. In the past century, 11 earthquakes of similar magnitudes have struck within 600 kilometers of Tuesday's earthquake.
