RE+-+Tsunamis


 * __How tsunamis form__**

Tsunamis are usually triggered by earthquakes. The crust shifting is the primary effect; a knock-on (secondary) effect of this is the displacement of waterabove the moving crust. This is the start of a tsunami.

A normal, wind-driven wave may have the length of a 100m from crest to crest, but a tsunmai may be 200km in length. The heights also greatly differ: 2m for a normal wave versus 1m for a tsunami out at sea. Tsunamis move at speeds of around 800kph, rapidly approaching the coast almost unnoticed. As they near the land they slow, reduce in length and gain in height.


 * __Japan Tsunami March 2011__**


 * __Facts__**
 * The tsunami happened on Friday 11th March 14:46 Japan time
 * Tsunami was triggered by a magnitude 9 earthquake on the Richter Scale


 * __Primary effects__**
 * Flooding of the land
 * Putting out fires
 * 88,873 houses, 3,970 roads and 71 bridges destroyed
 * Over 15, 281 people died


 * __Secondary effects__**
 * Radiation leak from the Fukishima nuclear power plant
 * Oyster fishing industry destroyed loss of jobs
 * Economic slow-down as companies like Toyota had to stop production
 * People leaving coastal towns forever due to fear of another tsunami
 * Large amounts of debris crossing the Pacific Ocean and potentially hitting the USA
 * Fires from burst gas pipes


 * __Short-term responses__**
 * Putting out fires
 * People were rescued by helicopter
 * Companies such as Japan Emergency NGO started to rebuild houses
 * The Japanese Government have set an Aid budget of £2.8 billion
 * Temporary pre-fab houses set up in Rikuzentakata
 * Temporary schools set up


 * __Long-term responses__**
 * Clearing the 20 million tonnes of debris from the tsunami
 * Tsunami detection and warning systems to be upgraded across the whole of the Pacific
 * Building a 15m high sea wall in Rikuzentakata
 * Rebuilding houses and businesses

A collection of excellent BBC videos: The Asian Tsunami: Causes and effects - [] The Asian Tsunami: Damage to coral reefs - [] The Asian Tsunami: Disease - [] The Asian Tsunami: Effects on tourism - [] The Asian Tsunami: Eyewitness accounts in Sri Lanka - [] The Asian Tsunami: Predicting a future event - [] The Asian Tsunami: Variable impacts - []

Awesome series of animations - []

__**The effects of the Boxing Day tsunami 2004**__

The earthquake that caused the Boxing Day tsunami was estimated to be between 9.0 and 9.3 on the Richter scale - one of the largets earthquakes ever recorded. The tsunami then moved as a series of r'ipples' across the Indian Ocean which built up as massive waves when they aprroached the land. It was one of the worst natural diasters in history - nearly 300,000 people killed or disappeared completely. Loss of tourismt income as tourists stayed away from the effected areas.



__**Responses to the tsunami**__


 * Immediate responses**
 * clean water, food, tents and plastic sheeting arrived as aid
 * $7 billion was donated worldwide for the affected countries
 * people in the UK donated £300 million (more than the government)
 * The UN's World Food Programme provided food and for more than 1.3 million people

> media type="youtube" key="R-jlyfzGP-o" height="297" width="410"media type="youtube" key="4bIFUosjKkY" height="298" width="443"
 * Long-term responses**
 * tsunami warning system - the disastrous effects of the Boxing Day tsunami led to the setting up of a tsunami early warning system in the Indian Ocean. Formal warnings are now sent to countries throughout the region if there's a tsunami threat. These warnings are then passed on to indvivduals via radio, television and e-mail or by bells, megaphones and loudspeakers attached to mosques
 * restoring mangrove swamps - the tourist industry in Thailand and Sri Lanka had grown rapidly before the tsunami. Many coastal areas had been cleared of mangrove swamps to make way for hotels.But mangroves act as a natural barrier - absorbing wave power and helping to protect coastlines and inland areas from tsunamis. After 2004, some projects to restore mangroves were started e.g. the Green Coast Project in Aceh, Indonesia. The new mangroves will help to increase the protection forfutrue tsunami, and also help to provide a livelihood for people affected by the 2004 tsunami, because mangroves are good breeding ground for fish.