Yikes! my office just shook pretty hard a minute ago. I checked for recent activity at the Pasadena US Geological Survey but nothing is registered yet. Ah... it is listed at US Geological Survey site at http://quake.usgs.gov/recenteqs/Maps/117-34.htm, and on the Southern California map... http://earthquake.usgs.gov/shakemap/sc/shake/... and Pasadena is listing it now.
It was only about four or five seconds, but the jolt was definitely felt here! If you felt it, you may want to report it to the US Geological Survey.