Yesterday (October 20th), we here in the South end of the San Francisco Bay Area had a moderate 5.6 earthquake (officially designated by the USGS as event nc40204628). We were fine, even if the kids were a little rattled. (I had to explain to them that earthquakes are part of living in California.) I tried to call my parents to see if they felt it, but got the dreaded “all circuits are busy” on our standard AT&T line. Not too surprising. What surprised me was that my Sprint mobile was also not working, but rather than a decent message, it…