The epicenter was about 5 miles deep, 4 miles south of Alamo in unincorporated Contra Costa County and 5 miles west of Danville, according to USGS.
It struck just after 4:30 a.m. and a Danville resident said it seemed to last longer than the small jolts that occurred on Saturday night and Sunday morning and the bigger ones that shook on Friday morning in the same areas.
