You know, I've mentioned occasionally viewing webcam videos from Japan before--the scenery is beautiful, and I find it relaxing.
I noticed once a few weeks ago that the image seemed to tremble momentarily. At first, I thought I'd imagined it. Then I thought maybe the wind was shaking the window the camera was looking through, or possibly it was a passing train, or someone walking by the table where the camera was sitting. Or maybe the camera was on a tall pole where the wind could affect it more easily. It wasn't just in one location, either--I've seen it in a few.
But I saw the image move probably 12 times while watching briefly today, and much more vigorously than before. Given the recent increase in seismic activity around the Pacific, as well as the recent earthquake...I'd guess these must be tremors, if not technically aftershocks.
Yet things like cars keep moving (You probably couldn't feel it while inside a moving car, I guess.). I doubt you could miss the event while inside the building, though, especially on an upper floor.
I guess it's particularly amazing to me coming from somewhere where seismic activity is much less common. Activity seems much more intense now than it was before, but it's still hard to imagine the earth moving being something that's, I guess, anticipated every few weeks or so. I wonder how frequent it really is? Not for nothing are those bigger buildings built to tolerate earthquakes, that's for sure!
This probably explains why I noticed recently that a few cameras had changed their angle slightly, too....