A preliminary magnitude 4.9 earthquake rattled the Bay Area shortly before 1:45 a.m. Thursday, shaking awake sleeping residents and surprising people with alerts to their phone. According to the U.S. Geological Survey, the earthquake was centered near Boulder Creek, an unincorporated area in the Santa Cruz Mountains. There were no immediate reports of injuries or damage, although the shaking was widely felt throughout the region.
A ShakeAlert was sent to phones warning of the earthquake as it hit. The service, which is used throughout the West Coast, is meant to give people a warning immediately before a large earthquake hits. The ShakeAlert warned a 5.0 earthquake was in progress; that initial magnitude was taken down slightly to a 4.9.Â