Risk that recent Tsunami could happen again
Tsunamis in the past, Tsunami facts, history, pictures, charts and photos, Tsunami sattellite images, Tsunami videos, what is a Tsunami and how are Tsunamis caused? How lives can be saved in future.

No one will ever know how many died in the 2004 Tsunami because so many of the towns and villages affected were in remote areas with few records of population. It is possible that more than 200,000 were drowned or buried in mud in just a few minutes. The worst affected areas were close to the earthquake epicentre, but the wave caused destruction as far away as India and Africa (East Coast).

Tsunami of December 2004

Could Tsunami deaths have been prevented?

Many scientists had been warning of the risks of a severe Tsunami in the region, and continue to warn of future Tsunami risks. The 2004 Tsunami was caused by a major shift in part of a well-known fault line. The result was an increased pressure on other parts of the fault, making further earthquakes more likely.

We never know when a major earthqake will happen. Tsunami waves travel very fast, and it is impossible to provide warnings for those very close to the earthquake zone which generates the wave. However, it is certainly possible to provide other coastal areas further away with adequate time for many people to get out of danger by moving to higher ground.

These signs are now found in many coastal areas
in countries like Thailand - warning people to flee
the coast if they feel an earthquake

Tsunami warning systems are now in place across the region most affected in December 2004 and were used during a recent tremor (April 2005). If they had been working earlier, it is possible that many tens of thousands of lives would have been saved.

What is a tsunami?

How are Tsunamis formed? Tsunamis are caused by sudden movement of the sea bed, during an earthquake or volcano. The result is a ripple of waves, just as if you dropped a large stone into a pool. Tsunami waves can travel at over 400 miles an hour through deep ocean, but don't usually cause any trouble at that stage to ships or boats. That's because the water is deep and the waves are long. Ships and boats just rise and fall gently - and may have no idea that a Tsunami wave has just passed beneath them.

Earthquake causes slide of sea bed and Tsunami wave

However as the wave approaches land, the water becomes more shallow and all the wave energy is concentrated into a very small area. The Tsunami wave slows down and increases in height. It is unusual for the wave to break: more commonly it just looks like a massive tide of water sweeping into the shore. Tsunamis are often called tidal waves, and pictures often show tsunami waves over 30 metres high breaking over the coastline, although the reality is more that the water level rises rapidly, and later falls just as fast.

Tsunami wave breaking onto coast of China - not the 2004 Tsunami

In the 2004 Tsunami, much of the damage was done by seawater returning to the ocean, and also by a second wave a few minutes after the first.

Tsunami wave facts - speed and depth

Here is some useful data showing how the speed of a Tsunami wave falls as it approaches land, and how the height rises. You can see the graph more clearly, and print it out, by right-clicking on the image and saving it first.

How often do Tsunami waves happen?

Tsunamis happen far more often than most people realise. Hawai sees a small tsunami every year and Alaska, Californai, Oregan, Washington, Japan, Indonesia, Malaysia, Philipines, India and other parts of the world can all expect to experience larger or smaller tsunamis in the future.

Tsunami earthquakes are those where there is a major shift of the seabed as two tectonic plates slide against each other, releasing forces many times as great as an undersea nuclear bomb.

Satellite images of 2004 Tsunami

Tsunami satellite images of before and after

Tsunami videos

Tsunami videos can be very upsetting to watch if they show the reality of what happens when a mega Tsunami hits land, buildings and people. It is shameful that some people see such things as entertainment. It is impossible to understand the full power of these waves unless you have seen one.

Many Tsunami videoclips from TV news reports and individuals - destruction in India, Thailand, Malaysia, Sri Lanka, rescue efforts and humanitarian help

Tsunami video - dramatic film clip taken by a holiday maker as a huge Tsunami wave sweeps up the beach and into the restaurant of the hotel, showing footage of Tsunami damage, tsunami wave pictures of tsunami victims and scale of tsunami disaster. Sad to see the video is listed in an entertainment area - warning: may be unpsetting to younger children.

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