Santa Ana - As mysteries go, it might not rank up there with "What happened to Amelia Earhart?" or "Did Oswald act alone?" but a strange rattling, shaking, and quaking got people in Orange County all shook up yesterday evening...and we can tell you this much, it wasn't an Elvis sighting either.

We are used to earthquakes in the Southland, but this was no quake either! Or a sonic boom.

Yikes! What was it?

Well, uh, we still don't know.

Dave Lopez was on the scene to investigate what made the Earth move yesterday under his feet and everyone's else's -- around 9:15 p.m.

Windows shook, nerves were rattled, dogs barked and everyone thought, maybe, we were getting ready for the big one. More than 70 calls were logged into 911 by frightened folks thinking someone was breaking into their homes.

Experts still don't know what caused the shake and the shimmy.

At least, and this is the good thing, the sky did not come tumbling down.