Tsunamis are characterized by several distinct wave features:
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Long Wavelength: Tsunami waves have very long wavelengths, often exceeding 100 kilometers (about 62 miles) between wave crests. This is in contrast to typical ocean waves, which have much shorter wavelengths.
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High Speed: Tsunami waves can travel at speeds of up to 500-800 kilometers per hour (about 310-500 miles per hour) in deep water. This rapid movement is comparable to the speed of a commercial jet.
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Low Amplitude in Deep Water: In the open ocean, tsunami waves have a small wave height (amplitude), usually less than a meter. This makes them difficult to detect and often go unnoticed by ships at sea.
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Wave Amplification Near Shore: As tsunami waves approach shallower coastal waters, their speed decreases, and their height can increase dramatically—sometimes reaching heights of over 30 meters (about 100 feet) or more upon impact, leading to devastating effects.
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Series of Waves: Tsunamis often come in a series of waves, known as wave trains. The first wave is not always the largest, and successive waves can be larger and more destructive.
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Long Period Between Waves: The time between tsunami waves can vary significantly, ranging from a few minutes to over an hour, which can mislead people into thinking that the danger has passed after the first wave.
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Directionality: Tsunami waves can travel across entire ocean basins and can affect coastlines regardless of their proximity to the earthquake or other event that generated them.
Overall, the unique features of tsunami waves differentiate them from typical sea waves and contribute to their potential for widespread destruction when they impact coastal areas.