A 2.9 magnitude earthquake shook Oakland at 2:55 PM today, with its epicentre north of Montclair. San Ramon also experienced continued tremors, including quakes of 2.9 and 2.6 earlier in the afternoon. UC Berkeley seismologist Roland Burgmann said the activity is a “flare-up” of November’s swarm, noting these quakes come and go without a major event developing.