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What Are Tidal Waves?

Tsunamis, often referred to as tidal waves, are a series of ocean waves caused by any type of sudden motion on the ocean floor. The motion could be caused by an earthquake, volcanic eruption, landslide or meteorite crash. Tsunamis throughout history have caused great destruction and devastation.

  1. Location

    • While tsunamis occasionally occur in the Atlantic and Indian oceans, they are most frequent in the Pacific Ocean. Tsunamis are most frequent in the region of the Pacific known as the ring of fire, which is a region surrounded by volcanoes that experience frequent earthquakes due to frequent tectonic plate movement. As many as four out of every five tsunamis occurs in the ring of fire region.

    Strength

    • The strength of the tsunami waves depends on the severity of the event that caused the water displacement. If sufficient force is not generated, tsunamis will either not form or will dissipate before they reach land. Earthquakes need to be higher than 6.5 on the Richter scale to cause a tsunami. Tsunamis can travel thousands of miles and still maintain enough energy to cause serious damage. An earthquake in Chili in 1960 caused destructive tsunami waves in Hawaii and Japan.

    Speed

    • Tsunami waves travel quickly across the open water at high speeds, and are often unnoticed out in the deep ocean. They are capable of traveling at speeds of about 500 miles per hour in the open water. As they reach shallower depths, their energy is directed upward due to the sloping ocean floor. This upward surge in energy causes the waves to swell to up to 50 feet in height before they break.

    Warning Signs and Systems

    • If the event that caused the water displacement is detected by scientific equipment, it can serve as a warning sign for a potential tsunami. If an earthquake or other event occurs close to the shore, tsunami waves can begin within minutes, so there really isn't time for warnings. While warning systems are in place in much of the Pacific Ocean due to the frequency of activity in this region, other areas, such as the Indian Ocean, do not have warning systems in place because tsunami activity is rare there. A receding ocean is a natural sign that a tsunami is imminent. This warning sign provides about a five-minute warning that tsunami waves are on their way.

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