Cathryn, although you have a small radius, you also start with a very small magnitude. You may not even find out whether there was such an earthquake....and most catalogues would be incomplete (I'm not sure exactly where Mt Diablo is-I fugure Bay area...near Parkfield since 1988 catalogues for 1.8+ would probably be complete.

So, if it woke you up, and you expected a 5, why do you start with 1.8?
Chris