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One of the emerging lessons of the earthquake-tsunami disaster is that mangroves and coral reefs are vital barriers that can prevent or at least soften the damage caused by tsunamis and high tidal waves.

A tsunami (Japanese: 津波 [tsɯnami], lit. 'harbor wave';[1] English pronunciation: /suːˈnɑːmi/ soo-NAH-mee) or tidal wave is a series of water waves (called a tsunami wave train[2]) caused by the displacement of a large volume of a body of water, usually an ocean, but can occur in large lakes.

Many early geological, geographical, and oceanographic texts refer to tsunamis as "seismic sea waves."

An earthquake is what happens when two blocks of the earth suddenly slip past one another. The surface where they slip is called the fault or fault plane. The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called

the epicente

How are earthquakes recorded? Earthquakes are recorded by instruments called seismographs. The recording they make is called a seismogram. (figure 4) The seismograph has a base that sets firmly in the ground, and a heavy weight that hangs free. When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the hanging weight does not. Instead the spring or string that it is hanging from absorbs all the movement. The difference in position between the shaking part of the seismograph and the motionless part is what is recorded.