P waves (aka primary waves) are the fastest waves. It's a seismic body wave that shakes the ground back and forth in the same direction and the opposite direction as the direction the wave is moving.
S waves (aka secondary waves) move through the earth by causing particles in rocks to move side to side
This is why S-waves arrive as secondary waves at the Earth's surface. There is another importantdifference between P-waves and S-waves. Although both can pass through solid rock, only P-waves can also pass through gases and liquids.
El Niño is a weather pattern that occurs in the Pacific Ocean. During this time, unusual winds cause warm surface water from the equator to move east, toward Central and South America.
