waves are basically of two types: body and surface waves. Body waves are generated to the release of energy at the focus and move in all traveling through the body of the earth. the name body waves. The body waves interact the surface rocks and generate new sets of waves surface waves. These waves move along the The velocity of waves changes as they travel materials with different densities. The denser material, the higher is the velocity. Their direction changes as they reflect or refract when coming materials with different densities. move faster and are the first to arrive at the These are also called ‘primary waves. The P- are similar to sound waves. They travel through liquid and solid materials. S-waves arrive at the with some time lag. These are called secondary and they can travel only through solid materials. statement 1 is correct. vibrate parallel to the direction of the wave. exerts pressure on the material in the direction of propagation. As a result, it creates density in the material leading to stretching and of the material. The direction of vibrations of is perpendicular to the wave direction in the plane. Hence, they create troughs and crests in material through which they pass. Surface waves considered to be the most damaging waves. Hence 2 is correct.