An earthquake is 0.8 likely to set off your burglar alarm; a burglar is 0.9 likely to set off your burglar alarm. And - we can't compute this model fully without this info - the combination of a burglar and an earthquake is 0.95 likely to set off the alarm;

I don't think that true. The earthquake can cause the burgler to have less control over his own movement and therefore increase the chance that he triggers the alarm.