PETROLIA, Calif. – A magnitude 4.1 earthquake shook some Northern California communities early Tuesday morning.According to the U.S. Geological Survey (USGS), a magnitude 4.1 earthquake was reported about 13 miles west of Petrolia in the Pacific Ocean just after midnight Tuesday at a depth of about 12 miles.HOW TO WATCH FOX WEATHERAccording to reports on the USGS website, shaking was felt by residents in communities such as Eureka and Fortuna.In addition, the USGS ShakeAlert system was activated, alerting people to the potential danger of the earthquake.Officials said the ShakeAlert system had estimated the earthquake to be at or above magnitude 4.5, so alerts were sent to cellphones.WHAT TO DO DURING AND AFTER AN EARTHQUAKESo far there are no reports of damage or injuries.On Monday, a pair of back-to-back earthquakes rattled the San Bernardino area in Southern California. Those earthquakes were measured as a magnitude 3.6 and a magnitude 3.0.Refresh this page and download the free FOX Weather app for updates on this story.