S waves, or secondary waves, are the waves directly following the P waves.
S waves travel in the same direction, but instead of being a compressive wave, they oscillate with a shearing behavior at right angles to the direction of motion.
Also S waves will not travel through liquids like water, molten rock, or the Earth's outer core.
In other words: S waves are more dangerous than P waves beacuse they have grater amplitude and produce vertical and horizontal motion of the ground surface
