Two mysterious booms have been heard around the San Diego area on Tuesday afternoon.Locals took to social media in their droves to question what had just happened.‘Was that a San Diego #earthquake?’ one Twitter user asked at 3.25pm. Another said that she had heard a ‘loud a** boom and then I felt an earthquake’.

Source: What caused two mysterious ‘booms’ that shook the earth around San Diego on Tuesday night? USGS say it was NOT an earthquake » The Event Chronicle