Several years ago, my family was eating dinner in our kitchen in Boston when suddenly, simultaneously, all of us had a sensation that was entirely new. Our chairs tipped backward for a moment, then righted themselves, but in a curvy sort of way like cresting an ocean wave. This completely novel experience left us in a state of experiential blindness, so we started forming hypotheses.
My experience of the big east coast earthquake with the epicenter in Virginia was similar to this, except I was lying down at the time and it was at least ten seconds. The sinusoidal nature of the shaking was apparent. I think I immediately recognized it as an earthquake despite no prior experience, because I didn't have any alternative hypotheses.
