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What Are the Two Main Types of Water Waves in the Ocean?

Ocean waters change continually as the winds and breezes blow across the water. These winds produce waves, the height of which is mainly determined by the depth of the water beneath the wave and the incline of the ocean floor. Classifications of waves vary; shallow and deep waves and longitudinal and transverse are two examples.

Terminology
- Understanding ocean waves requires knowledge of three terms. The first term is amplitude, or the height of a wave. Height is measured from the ocean surface to the high point of each wave. The second term, wavelength, defines how far each wave is from the next wave. Some days may have slow, rolling waves far apart; others may have one wave after another with seemingly no space in between. A third term is period, or the time between each wave, which differs from wavelength which measures distance.
Deep Water Waves
- Deep water waves are examples of the force of the wind in moving water. They can be described by the movement of the water in two directions. Longitudinal waves move parallel to the ocean floor while transverse waves move perpendicular to the sea floor. Deep water waves exhibit both features, with the water moving up and down like a transverse wave as the wave reaches its amplitude. At the same time the water moves parallel to the bottom in a circle that increases in diameter the closer the water is to the surface, like a longitudinal wave.
Shallow Waves
- Shallow waves, the type that break as they approach the beach, represent the force of the ground transforming deep water waves into shallow breakers. Shallow waves vary greatly from beach to beach depending on the slope of the ocean floor. The shorter the distance between the ocean floor and the ocean level, the greater the force. For example, if there is a sandbar 100 feet from the ocean's edge in very shallow water, then the waves will break there instead of making it all the way to the shore.
Tsunami
- The tsunami wave, like the one that struck Japan on March 11, 2011, demonstrates the force of the ground under the ocean affecting a deep water wave. Normally, the ocean floor has little effect on deep water waves due to the distance between the ocean surface and floor. An earthquake under the water changes everything. The force of the earthquake creates a special type of powerful waves that are sent out at great speeds and with great force.

Nature