FAQ about Tsunami - from the "Disaster Pages of Dr. GEORGE P.C." 1

Japan's Tsunami (2011)

Frequently Asked Questions About Tsunami and the International Tsunami Warning System

What generates tsunami?


Tsunami(s), also called seismic sea waves, are a series of waves generated by large, violent earthquakes occuring near the ocean. Not all earthquakes generate tsunamis.By far, the most destructive tsunamis are generated from large shallow earthquakes with an epicenter or fault line near or on the ocean floor. Vertical displacements of the earth's crust along the rupture, resulting from such earthquakes, can generate destructive tsunami waves which can travel across an
ocean spreading destruction across their path. Similar displacements of the ocean floor can also be produced by volcanic eruptions and submarine avalanches, or submarine landslides. However, these sources are considered as point sources and , although destructive locally, the energy of the waves is rapidly dissipated as they travel across the ocean. 
The wave crests of a tsunami may be a hundred kilometers or more apart as they travel across the ocean. The height from trough to crest may be only a few centimeters or meters in the open ocean. A tsunami cannot be felt aboard ships in... Read the whole article here !