TSUNAMIS

WHAT IS A TSUNAMI?

A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion.TSUNAMIS ARE NOT TIDAL WAVES. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water.With typical waves, water flows in circles, but with a tsunami, water flows straight.That is why tsunamis cause so much damage!

HOW ARE TSUNAMIS GENERATED?

Tsunamis are generated by any large, impulsive displacement of the sea level.The most common cause of a tsunami is sea floor uplift associated with an earthquake.Tsunamis are also triggered by landslides into or under the water surface, and can be generated by volcanic activity and meteorite impacts.

HOW OFTEN DO TSUNAMIS OCCUR?

On the average, two tsunamis occur per year throughout the world which inflicts damage near the source.Approximately every 15 years a destructive, ocean-wide tsunami occurs.

HOW FAST DO TSUNAMIS TRAVEL?

Tsunami velocity depends on the depth of water through which it travels.Velocity equals the square root of the product of the water depth times the acceleration of gravity.Tsunamis travel approximately 475 mph in 15,000 feet of water.In 100 feet of water the velocity drops to about 40 mph.

HOW BIG IS A TSUNAMI?

Tsunamis range in size from inches to over a hundred feet.In deep water(greater than 600 feet),tsunamis are rarely over 3 feet and are not normally noticed by ships due to their long period or time between crests.As tsunamis propagate into shallow water, the wave height can increase by over 10 times. Tsunami heights vary greatly along a coast. The waves can be amplified by shoreline and sea floor features. A large tsunami can flow low-lying coastal land over a mile from the coast.

TOP 5 TSUNAMIs:

1 Indonesia

In the west coast of Sumatra, the most terrifying tsunami happened on December 26 2004...After an earthquake of 9 on the righter scale, a giant tsunami happened.Over 200000 people died.

2 Greece

1410b.c. after an earthquake, a tsunami reached over the north coast of Greece.Over 100000 people died.

3Portugal

November 1st 1755 an earthquake known as the great Lisbon earthquake had a magnitude of 8.5-9 on the moment magnitude scale.The water height was 12.20m. Over 6000 people died.

4 South China sea

On May 22 1782, an earthquake of 7.0 in the earthquake magnitude happened.About 40000 people died from the tsunami.The water height still remains a mystery.

5 Indonesia(Krakatau)

On August 27 1883, a tsunami that was 35.0m high happened in Indonesia.About 36500 people died from the tsunami.

which country is best prepared for tsunamis and why?

The most prepared country for a tsunami is Japan. The country that most often experience tsunamis are Indonesia and Japan.One of the reasons Japan is most prepared is because of their warning system.Another reason is because Japan's citizens are not selfish.The owners of the shops that survived put themselves in other people's shoes, and they know that some people have families, they have no clothes, food or water.So the owners open their shops after the tsunami.I bet a million bucks if a tsunami hit Singapore we would not be this kind.If the shops were open i see no reason people should have to report break ins or robbery.

another reason japan is best prepared for tsunamis

A tsunami happened on 11March 2011 in Japan, what I want to highlight, however, isn't the disaster, but the manner in which the Japanese people responded to this terrible crisis.We all know the typical response immediately after a tragedy- chaos, looting, violence, mob mentality, and other look-out-for-yourself behaviours.But, for now anyways, that seems to be absent in Japan..Instead, we're seeing the spirit of the Japanese people stand strong despite the adversity.Instead of violence and looting the Japanese people continue to behave the way they behaved before the earthquake.This rapid return to normalcy, psychologists say, will help Japan more quickly recover.

another reason japan is best prepared for tsunamis

Think of it this way: if there's looting and mob violence, medical and security personnel will be on the scene to assist victims and enforce order.But since there isn't any of that in Japan so far, medical and security personnel can continue to focus on finding real victims from the earthquake and the tsunami.

ABOUT JAPAN'S WARNING SYSTEMS

Japan’s earthquake monitoring and tsunami warning system is one of the most sophisticated — and costliest — in the world, befitting an economically developed, seismically cursed nation that, on average, experiences a quake every five minutes.The monitoring system has been upgraded several times since its inception in 1952, and especially after a 7.8 magnitude quake in 1993 triggered a 30-meter high tsunami that devastated the coast of Hokkaido. The meteorological agency had issued a warning after the quake, but it came too late for the hundreds of people who were killed.

More about japan's warning systems

The tsunami warning service, which has at least six regional centers, currently sends signals from 180 seismic stations across Japan and about 80 water-borne sensors are monitored 24 hours a day by a computerised Earthquake and Tsunami Observation System (ETOS).

To get warnings out quickly, the Japan Meteorological Agency and media have developed a system to superimpose alerts on TV screens as soon as they are issued.

In addition, warnings are sent to local officials via a satellite system that acts as a back-up to land-based communications. Local officials activate sirens and loudspeaker systems, and also decide if an evacuation advisory is needed.