Swarms like this are not unusual for the region. As to whether this means some kind of bigger event is coming, one can say it is possible, but many other swarms have occurred without bigger, more damaging shocks. That said, big quakes have occurred in this region, including the 2010 Sierra El Mayor quake that clocked in at magnitude 7.2. The southern stretch of the San Andreas is also a threat for large quakes, in the range of 7.8 magnitude. This is the kind of event that can cause catastrophic damage and injure or kill thousands of people. We are not immune to quakes...
Even if nothing more comes of this swarm (which is the most likely outcome), the event should remind people that southern California does live under the threat of large damaging earthquakes, and that anyone who lives there owes it to themselves to be prepared. Have water, food, batteries, first aid supplies, and an emergency plan in place. Check out these resources for more information.
Postscript: USGS Field Office in Pasadena released this statement: (below the fold...)
