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 would simply hang up after trying to connect for a few seconds.
Today on SFGate.com I finally found some confirmation: Quake calls jammed cell phone networks. I’m sure that mobile networks use the same sort of modeling as traditional phone lines to predict and handle peak loads, but it’s starting to look like their maximum loads are much lower. My AT&T line was useful again in about 10 minutes and I was able to get on a conference call with India for an hour without any dropouts. My Sprint phone, on the other hand, was still dead an hour later. Not a good sign for anyone counting on their mobile in case of an emergency.