A shake alert went out over the U.S. Geological Survey's early warning system on Dec. 4, warning that a 5.9 earthquake near Carson City in western Nevada could produce heavy shaking in the region. But moments later, the survey announced the alert, which was sent to people as far west as San Francisco, was a false alarm.

A major, 7.0-magnitude earthquake struck near the Alaska-Canada border on Saturday, according to the United States Geological Survey. The temblor happened at 11:41 a.m. Alaska time about 56 miles north of Yakutat,