A tsunami (pronounced soo-NAA-mee) is a series of waves (called a "wave train") generated in a body of water by a pulsating or abrupt disturbance that vertically displaces the water column. Earthquakes, landslides, volcanic eruptions, explosions, and the impact of extraterrestrial bodies such as meteorites, can generate tsunamis. Tsunamis can savagely attack coastlines, causing devastating property damage, injuries, and loss of life due to injuries or drowning.

Tsunami waves travel underwater, which is how they can pass unnoticed out at sea, forming only a passing "hump" in the ocean, sometimes over a 100 kilometers long, until they reach landmass.

Indian Ocean tsunami - 26 Dec 2004

The 2004 Indian Ocean earthquake triggered a series of lethal tsunamis on December 26, 2004, with fatalities last reported at 120,000, ranging from those in the immediate vicinity of the quake in Indonesia and Thailand to people thousands of kilometres away in Bangladesh, India, Sri Lanka, the Maldives, and even as far as Somalia in eastern Africa. The death toll from this event makes it the deadliest tsunami in recorded history.

Unlike the Pacific Ocean, there is no organised alert service covering the Indian Ocean. This is in part due to the absence of major tsunami events since 1883 and an emphasis on developing a tropical cyclone warning system - the result "LOSS of over 1,00,000 lives"

Tsunamis caused by a magnitude 9.0 earthquake under the sea west of Banda Aceh on the island of Sumatra in Indonesia caused severe devastation in the form of death and loss of property on the coasts of the Indian Ocean, particularly Sri Lanka, Indonesia, India, Thailand (especially Phuket and Khao Lak, whe, Maldives, Malaysia, Myanmar, and Bangladesh; and also in Somalia, Kenya and Tanzania in Africa. Indonesia has faced the brunt of the devastation with over 80,000 feared dead. The number of deaths caused by this tsunami is expected to double due to wide spread illness such as cholera and malaria, caused in part by contaminated drinking water and lack of sanitary facilities. (WHO has stated that corpses are not a major public health concern and do not promote the spread of disease.) Many foreign tourists, especially Scandinavians, are among the dead.

Sri Lanka reports more than 24,000 dead, and at least 10,000 were killed in India.

Many who did survive are struggling to stay alive, and the World Health Organization estimates that five million people are without basic needs. Scenes of destruction were repeated across the region, as were the scenes of grief with residents and holidaymakers searching in vain for loved ones. In Sri Lanka's worst-hit area Ampara, residents ran relief efforts themselves, going round with loudhailers, asking people to donate pots and pans, buckets of fresh water and sarongs. People worldwide opened their hearts and wallets to give millions of dollars to help relief efforts, jamming phone lines and Web sites and outpacing governments in their generosity.

Displaced: Massive surge of sea water penetrated more than a kilometre inland, engulfing everything on the way. At Mullaitivu on the north-east coast, more than 20 villages have simply disappeared. Thousands of displaced people have sought refuge in government schools, marriage halls and other buildings. The region was already suffering due to 20 years of civil war and now this disaster has added to the people's difficulties. People have nothing to go back to their villages.

"The world hasn't got a real picture of what has happened here."