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What Causes Waves

What Causes Waves

Everybody gets amazed by those milky-white waves on the beach, but seldom do we try to figure out what causes them in the otherwise calm ocean.
Abhijit Naik
Wind-generated waves, informally referred to as ocean surface waves or simply as waves, are waves which occur on the surface of various water bodies. They may range from ripples caused on the surface of the lake to gigantic roller coasters. While the driving force behind these waves is mostly the wind, there do exist a few other factors which play a crucial role in their development on the surface of any water body.
What Causes Waves in the Ocean?
In order to understand that, you will have to do a small experiment. Take a shallow pan and fill it with water to the brim. Now stay one side of the pan and start blowing your breath into it. You will see the formation of small 'waves' on the surface of the water in the pan. The same goes into the formation of oceanic waves; the only difference is that the power of actual wind is much more than that of your blowing into the pan. So the waves in the ocean are bigger in size than the tiny ripples that you notice in the pan.
Wind
The most prominent factors involved in the formation of waves on a water body include wind speed, depth of the water, fetch (i.e., the distance covered by the wind), etc. Waves come in various shapes and sizes. The size of the wave depends on the velocity of the wind. The faster it is blowing, bigger will be the waves, which is why the waves that form during a storm, wherein wind speed is quite high, are bigger than the waves we see daily.
The wind speed, in turn, depends on the distance covered by the wind and the open area on which the wind is blowing. More the distance covered, more will be its power. And ocean surface being an open area, there are hardly any obstructions to resist and decrease the velocity of the wind. Both these factors play a crucial role in causing waves on the surface of the ocean.
Earthquake
While wind is the major factor when it comes to wave formation, even earthquakes can cause waves, and these waves, mind you, are a lot bigger and far more devastating compared to wind waves. Earthquakes occurring on the ocean floor have the propensity to trigger gigantic waves capable of sweeping across the coastal areas with immense ease. These waves are mainly caused as a result of the movement of tectonic plates beneath the ocean floor. When one tectonic plate, encroaches upon another, it gives rise to a sudden gust of water, which picks up speed as it travels and culminates onto the land in form of gigantic wave referred to as a Tsunami.
What Causes Them to Break?
Like the formation of waves, breaking of waves is also equally interesting. There are two factors which can cause a wave to break: shallowness of the water body and contrasting wave patterns. Waves that break as they near the shoreline actually break due to shallowness of water. As the wave approaches the land, the rising ground pushes it upward making the crest go higher and higher, until it reaches the maximum possible height and finally breaks.
On the other hand, the ones that break in the mid-ocean actually break as a result of collision with another wave coming from other direction. No two waves are the same, nor are their directions. In such circumstances, when two waves come face to face with each other and collide, it causes both of them to break.
Refraction occurs when a wave comes in contact with the shore, in such a manner that a part of it―at the forefront―touches the ground and slows down, while the remaining part continues to move at the same speed, thus causing the wave to bend.
So the next time you go to some beach, you are bound to experience a different kind of joy in watching those beautiful waves cruising their way into the land.
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