Tsnaumi

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tsunami is a series of extremely long ocean waves caused by a large and sudden displacement of the ocean, typically resulting from an underwater earthquake. National Oceanic and Atmospheric Administration (.gov) National Oceanic and Atmospheric Administration (.gov) +1 Key Characteristics Not Just One Wave: It is a "wave train" or a series of surges that can last for hours. Extreme Speed: In deep water, these waves can travel at over 500 mph (800 km/h)—the speed of a jet airplane. Stealthy at Sea: In the open ocean, the waves may only be a foot or two high and can pass under ships unnoticed. Height at Shore: As they reach shallow water, they slow down and "pile up," growing into a fast-rising flood or a "wall of water" up to 100 feet (30 meters) high or more. Wikipedia Wikipedia +4 Main Causes Undersea Earthquakes: The most common cause (about 80%), occurring when tectonic plates shift vertically. Landslides: Underwater or coastal landslides that drop massive amounts of debris into the water. Volcanic Eruptions: Explosions or the collapse of a volcanic flank into the sea. Meteotsunamis: Caused by rapid changes in atmospheric pressure from severe weather. USGS.gov USGS.gov +5 Warning Signs Ground Shaking: Feeling a strong or long-lasting earthquake near the coast. Receding Water: The ocean may suddenly pull back far from the shore, exposing reefs and the seafloor. Loud Roar: A sound similar to a train or a jet engine approaching from the ocean. Wikipedia Wikipedia +5 The word "tsunami" comes from the Japanese characters for "harbor" (tsu) and "wave" (nami). Scientists avoid the term "tidal wave" because tsunamis are not caused by tides or the gravitational pull of the moon. USGS.gov USGS.gov +3 Would you like to know about specific historical tsunamis or how the global warning system works?