The moment when a tsunami destroyed Pier No. 1 at Hilo Harbour, Hawaii, in 1946.

An 8-meter tsunami advances inland, Oahu, Hawaii, 1957, following a magnitude 8.6 earthquake 3,600km (2250 miles) away off the Aleutian Islands.

Tsunamis, or tidal waves, are caused by earthquakes and landslides under the ocean. A modest wave may be caused on the surface of the open ocean, but as it reaches shallower coastal waters it will be amplified. Tsunamis can cross entire oceans very quickly: an 18 meter-high (49 feet) wave hit Hawaii in 1946, 4.5 hours after a submarine earthquake off Alaska. The wave ravelled at 800km (500 miles) per hour. Vulnerable areas such as the US northwest coast have designated "tsunami safe" areas of higher ground, but the warning time depends on the distance of the source of the tsunami.

A coastal road and car park are inundated by a tsunami on Japan's east coast, May, 1983. 107 people drowned and $800 million of property was lost.

A fishing boat and crane-carrying barge dumped 75 metres from the dockside at Aonae, Japan in July 1993, after one of the largest tsunamis in Japan's history.