These are surface waves, which have a much greater amplitude on the earth's surface than P-waves (which are faster). It's pretty unlikely that anyone can feel P-waves unless they are fairly close to the epicenter. P-waves are also basically a very short pulse; the S waves, which come later, last a bit longer, but also may have relatively low amplitude, and then the surface waves come last and cause the most perceptible (and damaging) ground motion.

http://www.geo.mtu.edu/UPSeis/waves.html