"Indeed, even the largest earthquakes do not actually produce visible "ground waves". Reports of such are pretty much due to perceptual phenomena, such as inner ear and emotional inputs."

I beg to differ, having witnessed them myself. On the morning of Oct 1, 1987 I was looking north for 200-300 yards across a half empty parking lot in Buena Park as the Whittier Narrows earthquake was doing its thing about 12 miles to my northwest. Certainly the ground may have appeared to be rippling far more than it actually was, but I am highly dubious that it was 100% illusion.

Brian