Back in 1991 I lived in Yokohama teaching English, and was in two small (3.5 - 4 magnitude), and short (30-second) jishin, or earthquakes. The two-story wooden house I lived in shook back and forth. It was a bit scary, and these were just small, short 'quakes!
I know a man in Kawasaki, Tsunashima-san, who experienced the great Tokyo 'quake of 1923. He told me the earth kept shaking and shaking for what seemed like forever, and then "bang, bang, bang", the earth just seemed to drop three times and the earthquake was over.
MRPLUTO