Contrary to popular belief, a tsunami is not a huge tidal wave. It has absolutely nothing to do with the tides. A tsunami is really a seismic sea wave, the result of an undersea disturbance caused by earthquakes, submarine avalanches, volcanic eruption, or even meteorite impact. You can liken the effect to that caused by tossing a stone into a pond, and seeing the ripples radiate out in all directions. The difference is that these 'ripples' can climb to 67 m (220 ft) high, can be several kilometres long, and travel as far as 19,300 km (12,000 mls) at speeds up to a breathtaking 1,045 km/h (650 mph). Ironically, the tsunami could pass unnoticed to crews on ships out at sea, as the wave crests may be up to 100 miles apart, giving a wave height of no more than 1 foot. But when the tsunami enters shallow coastal waters, the wave length and velocity decreases causing the water to build up to unimaginable heights, before sweeping ashore with devastating force.

22nd. May 1960 - At 19:11 GMT, an earthquake with a surface-wave magnitude of 8.6 occurred off the south central coast of Chile. This created a Pacific-wide tsunami. The 8m (25 ft ) wave that crashed on the Chilean coast 10-15 minutes after the earthquake, obliterated three fishing villages, and killed over 200 people. Along the Peru-Chile coast the wave was up to 25m (77 ft) high, and the total loss of life caused by the earthquake and the tsunami was estimated at 5,700 people. The tsunami raced to Japan 17,000 km away at speeds up to 835 km/h (520 mph) where it killed in excess of 200 people. 14.8 hours after the earthquake, the 12m (40 ft) tsunami struck Hilo on the coast of Hawaii 10,000 km away from the source.,(See details below)

1st April 1946 - The Aleutian Trench, 2.1/2 miles below the surface of the North Pacific slipped, triggering a massive undersea earthquake. The tsunami wave of up to 115 feet travelling at 72 mph swept over the Aleutian islands 90 miles away, destroying everything in it's path including the lighthouse on Scotch Cap. Continuing it's journey, at an amazing average speed of 490 mph the tsunami crashed into Hilo, Hawaii, flooding the downtown area and killing 96 people. Overall the Hawaiian Islands lost 159 lives, 1,400 homes, and more than £26 million in damages.

May 1960 - (see Chile above) 14.8 hours after the earthquake in Chile, and 10,000 km away from the source, a 12m (40 ft) wave crashed on the coastline, leaving only reinforced concrete and steel structures remaining, and these were gutted. Those parking meters on the street that survived were bent horizontal to the ground. The estimated damages for the Hawaii islands came to $24 million with a loss of life of 61 people. A sad, but surprisingly low figure, when you consider the ferocity of the tsunami. The total estimated cost of this tsunami came to over half a million dollars.

1896 - In the Sanriku district in Japan, a giant tsunami more than 30m (100 ft) high, forced it's way almost 160k (100 miles) inland destroying everything in it's path. Entire townships were obliterated and their population drowned. In Kamaishi, all but 143 of 4,233 buildings were swept away, along with four fifths of the 6,500 strong population. At Haamaisi, 4,700 of the 6,500 inhabitants died. An official survey gave a total of 27,122 dead, 9,247 injured, and 10,617 houses swept away.

3rd. March 1933 - An earthquake generated a tsunami with 3,000 people killed, 8,000 ships sank, and 9,000 dwellings destroyed.

1964 - An Alaskan earthquake generated a tsunami with waves between 10 and 20 feet high along parts of the California, Oregon and Washington coasts. The tsunami caused more than $84 million in damage and killed about 123 people.

1st. November 1755 - Hot on the heels of the earthquake came the dread tsunami. The River Tagus seemed to ebb out to sea, then reared up to 50 feet high, and roared through the city in three waves. Thousands of people, survivors of the earthquake, were washed away. The wave spread to as far as the West Indies four hours later.

26th. August 1883 - The collapsing volcano (see my volcano page) turned the sea into a raging maelstrom swamping all the ships in the coastal areas. Seismic tidal waves (Tsunami) up to 130 ft high raced along the coasts of Sumatra and Java destroying 295 towns in it's path. North of Krakatoa the island of Sebesi was completely submerged, drowning all of the 3,000 islanders.

Fastest: 1,045 km/h (650 mph) Highest: 67 m (220 ft) Furthest: 19,300 km (12,000 mls)