by the United States government, Chapters (2002)
“ Either a tsunami or a storm tide that overflows the land is popularly called a tidal wave, although it bears no relation to the tide.If a volcanic eruption occurs below the surface of the sea, the escaping gases cause a quantity of water to be pushed upward in the shape of a dome. The same effect is caused by the sudden rising of a portion of the bottom. As this water settles back, it creates a wave which travels at high speed across the surface of the ocean.Tsunamis are a series of waves. Near the epicenter, the first wave may be the highest. ”
