Ocean waves have different names and they are classified according to their periods. Ripples are small waves caused by the wind blowing across the sea surface, and they have an interval of less than 0.5 seconds.
When waves travel in groups, they are called wave trains. A wave train is a group of wind-driven waves that occurs in deep water. Small versions of wave trains caused by a boat's movement are called swells. Tsunamis, on the other hand, are much more powerful. These are the largest and oftentimes most destructive and energetic waves on Earth. Tsunamis form in deep water, when the wind travels from five to 65 miles per hour, and can reach a height of 45 feet. They also form due to earthquakes, where the sea floor suddenly moves up and down, causing the water to spread in all directions.