The Calaveras fault branches off from the Hayward fault in the South Bay and runs up to Danville, generally on the west of Interstate 680 when you get between Sunol and San Ramon. It is connected ...

The first was a 2.7 magnitude tremor along the Hayward Fault at 5:03 a.m., followed by a 3.3 magnitude quake (revised down from 3.4) at 11:52 a.m., and a 3.2 magnitude event two minutes later.