Google has a program called DiRT (Disaster Recovery Testing)[0], when in a certain week of the year, some major exercises that simulating the loss of headquarters are carried out, including the (simulated) loss of some teams, some network connections in the headquarter and/or the physical access to the headquarters buildings. That makes a lot of sense when you place your headquarters at a place that can be demolished by an earthquake.
[0]: http://queue.acm.org/detail.cfm?id=2371516