" If the magnitude of an earthquake is to be compared worldwide, a measure is needed that does not depend (as does intensity) on the density of the population and type of construction. A strictly quantitative scale that can be applied to earthquakes in both inhabited and unhabited regions was originated in 1931 by Charles Richter in California. .

             "Because the size of earthquakes varies enormously, the amplitudes of the ground motions differ by factors of thousands from earthquake to earthquake. It is therefore most convenient to compress the range of wave amplitudes measured on seismographs using some mathematical device" (Bolt 118).

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             The first earthquake recorder described in any detail was an artistic device invented by the Chinese scholar Chang Heng about 132A.D. The instrument was a seismoscope: unlike a seismograph, it did not give the complete time history of earthquake shaking but simply the direction of the principal impulse due to the earthquake. .

             Along seacoasts, another disaster may follow large earthquakes. .

             "The sudden offset of a major fault under the ocean floor moves the water as if it were being pushed by a giant paddle, producing powerful water at the oceans surface. These water waves spread out from the vicinity of the earthquake source and move across the ocean until they reach a coastline"(Van Rose 100).

             References to the devastation of tsunamis can be found throughout history. The earliest description is of a damaging sea wave near the north end of the Aegean Sea in 479B.C. One of the worst tsunamis in history hit the eastern coast of Honshu following a great earthquake centered out at sea on June 15, 1896. The seismic sea wave washed onto nearby land as much as 25 to 35 meters above high tide level. Entire villages were engulfed. More then 10,000 houses were washed away, and 26,000 people were killed. Within the last 200 years alone, about 3000 tsunamis have produced fatalities.