SACRAMENTO, Calif.—As sensors picked up the first signs of a strong earthquake jolting the Northern California coast, an alert was blasted to 3 million smartphone users telling them to “drop, cover, hold on.” It was hailed as the biggest test yet of the warning system since its public launch.
But the people most rattled by the magnitude 6.4 earthquake early Tuesday said the alert didn’t give them enough time to take cover as the temblor shook homes off foundations, knocked out power and water to thousands, and injured more than a dozen people.
