Sea waves travel as up-and-down vibrations: the water moves up and down (without really moving anywhere) as the energy in the wave travels forward. Waves like this are called transverse waves. That just means the water vibrates at right angles to the direction in which the wave travels.
Subsequently, one may also ask, what is the definition of compression waves?
Mechanical longitudinal waves are also called compressional or compression waves, because they produce compression and rarefaction when traveling through a medium, and pressure waves, because they produce increases and decreases in pressure. Transverse mechanical waves are also called "shear waves".
What is rarefaction and compression?
However instead of crests and troughs, longitudinal waves have compressions and rarefactions. Compression. A compression is a region in a longitudinal wave where the particles are closest together. Rarefaction. A rarefaction is a region in a longitudinal wave where the particles are furthest apart.
Why do compressions and Rarefactions happen?
Waves are made up of compressions and rarefactions. Compression happens when molecules are forced, or pressed, together. Rarefaction is just the opposite, it occurs when molecules are given extra space and allowed to expand. Remember that sound is a type of kinetic energy.