XXXXEarthquakes beneath the ocean floor sometimes create big sea waves or tsunamis. These waves travel across the ocean at speeds as great as 597 miles per hour and may be 49 feet high or higher by the time they reach the shore. During the 1964 Alaskan earthquake, tsunamis engulfing coastal areas caused most of the destruction at Kodiak, Cordova, and Seward and caused severe damage along the west coast of North America, particularly at Crescent City, California. Some waves moved across the ocean to the coasts of Japan.

XXXXA tsunami is a series of waves, created in an ocean or sea by an impulsive disturbance that displaces moves the water. Earthquakes, volcanic eruptions, explosions, and the impact of meteorites can generate tsunamis. They can relentlessly attack coastlines, causing awful property damage and even death.

XXXXTectonic earthquakes are particularly associated with tsunami; when they happen to occur under the sea, the water above the earthquake is moved from its stable position. Waves are created as the displaced water, which moves with gravity, attempts to regain balance. When large areas of the ocean floor move vertically, a tsunami can be made.