Did The Earth Shake Last Night?

I woke up all of the sudden last night/early this morning and my bed was shaking too and fro. No, my wife was not having one of her sex dreams, she was perfectly asleep until afterwards, when she woke up and confusedly told me to go back to sleep. I'm just wondering if there was an earthquake in the Los Angeles area last night. I checked the Yahoo news page but only found references to an earthquake in Africa, which, while being strong, probably did not contribute to my bed shaking around like it was playing in a Moon Bounce.

Now, there might be a more paranormal explanation rather than a geological one. My wife is convinced that our house is haunted. I think some people might have died of old age/disease in it before my father in law acquired it, and these ghosts might still be haunting the house. She's had some strange (non-drug related) occassions where she thinks she heard a voice telling her to wake up and sometimes she felt something move her or heard something in another room.

What if what was shaking my bed last night was an irate ghost? If someone doesn't tell me that there was some sort of seismic activity in southern California last night, I'm going to have to assume that it was. Now, I just need to know where I stashed my Positronic Ionizing Conductor so I can trap this ghost without having to call the actual GhostBusters.