Tsunami - The unstoppable phenomena

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Civilizations have been washed away by these huge waves millions of people have died during the past, but how is a tsunami created? Not that many know how this phenomena works. We have also never been able to stop or prevent these disasters, but why? Is it impossible?

April Fool’s Day 1946, a day for pranks everywhere, except Hilo, Hawaii. Some fishermen were out fishing a morning, and the sea decided to play a trick on them. Suddenly the ocean rushed out. The fishermen, quite aware of the danger, rushed to shore to warn the town of the coming disaster, but they did not get any response.
A total of 165 people died and damages for $26 million. This catastrophe is called April Fools Day Tsunami by the locals due to the fact that people thought that the tsunami warnings that day were an April Fools prank! It was just a mistake, but the outcome of it was devastating. We will discuss more about this event later in the article.

This phenomenon can be described as a series of waves created when a mass of water (in this chase, an ocean) is rapidly displaced on a massive scale. The causes behind this can be either an earthquake, landslide, volcanic eruptions or large meteorite impacts. But the cause that generates the most tsunamis is by far earthquakes. The effect of a tsunami does not always have to be devastating; there are several occasions where a tsunami goes by unnoticed.
The term Tsunami was created by a fisherman that returned to port, finding the entire harbour with surroundings devastated, but still, he never noticed anything while he was out on the sea? You can not notice a tsunami on the surface, even out on deep ocean, because it has much smaller amplitude (wave heights) offshore and a huge wavelength. The only thing you can notice is a slight “hump” passing by in the ocean. As mentioned earlier, the most common cause for a tsunami is earthquakes, or to be more specific; undersea earthquakes.
Even it the earthquake itself is too small to generate a tsunami, it may trigger an undersea landslide which in turn is very capable of creating a tsunami! When this happens the sea floor suddenly deforms and vertically displaces the water above, creating plate boundaries.
The kind of earthquake that creates tsunamis easiest is the subdcuction earthquake, where denser oceanic plates slide under continental plates. When this occurs, the energy moves in all directions out from the source. You can compare this to throwing a pebble into a small, still pond. The ripples that move from the source represent the energy which in turn creates the waves. As mentioned, the waves are unnoticeable out in the deep ocean, but when they get closer to the shore, they get higher and compressed.

So how can you then notice an approaching tsunami? Fortunately, there are a number of things that, according to scientists, is associated with tsunamis. Here is a quotation of those things:
o An earthquake maybe felt
o A large amount of gas can bubble to the water surface
o The water in the waves could be unusually hot
o The water may smell like rotten eggs (hydrogen sulfide), or of petrol or oil
o The water may sting the skin
o A thunderous boom may be heard followed by a roaring noise as of a jet plane
o The ocean usually recede to a substantial distance
o A flash of red light might be seen near the horizon
o As the waves approaches, the top of the wave may glow red

But even now when we are aware of these things that show us when a tsunami is approaching, we still cannot exactly prevent them, or even less stop them. But there is several warning system that has been developed, and even more that currently is being developed. But there is still no system that can detect a tsunami out in the deep ocean, when its wave height still is low. The very first warning centre was established after the 1946 disaster in Hilo, Hawaii. Although, there is still no system that really works, since 1948, 75 % of all warnings issued have been false! For example, in 1948 Honolulu was evacuated on a false alarm, which cost them more than $30 million. Some countries have built walls that slows down the tsunami and takes away some of its power, some have built channels or tunnels to lead masses of water away. But none of these works perfectly, far from that!
They are still a positive step forward, they decrease the power of a tsunami, and that can be very important. If we only could develop this, and make progress forward, there will be less damage in the future.

But thanks to the fact that there is no perfect-working system, there is hardly any city or civilization that can evacuate in time, or is able to warn the ones who might be affected. Until a good-working warning system is established, hundreds of thousands of people will die in the future, and there is nothing we can do about it. Cities will continue to be swept away; countries will continue to be devastated. The consequences are huge, out of range. Even hard to imagine!

When these gigantic waves hit the shore, it washes away everything in their way, nothing is left untouched. Cities gets demolished, people washed away to nowhere. So of course this has a huge effect on the economy in the country, but also on the environment of course. As a comparison, the wave that hit Hilo in 1946 was 115 ft high! It was created by an earthquake (7.8 on the righter scale) outside the Aleutian Islands, which is all the way up near Alaska. Just imagine how devastating it was when the waves it hit the shore, buildings were destroyed and people gets panic, running around, don’t knowing what they can do to rescue them self. Some may realize that there is nothing they can do against this nature phenomenon, they just stand there and wait to be washed away.
That tsunami had a huge effect on the economy due to all the buildings and repairing that had to be done, and not to mention the “cleaning” of the area. It was estimated that it cost approximately $26 million! But fortunately, many other countries sent aid, except that help, it would be very difficult for them to manage everything. Another thing to take in mind is that the cleaning may take several years, and that could most likely cost millions of dollars. So afterwards, when everything was back to normal, the affected country (Hawaii, USA) had huge debts which in turn will take a while to pay back. Then think of how damaged the environment was, debris all over the ground, trashed houses, furniture and all kinds of stuff laying everywhere. It will also take some years for the nature and the eco-system to get back to normal again. A country that has been exposed for a tsunami will be in a kind of depression for the forthcoming years.
It is very difficult to presume how long it is going to take though, but it will most certainly happen. Besides all of these terrible consequences, families will also be shattered in the chaos that comes with a tsunami, and many will die. There is also a big psychological pressure when you lose one or several family members, and you will probably feel lost for a period of time. It is very difficult to handle a disaster of this size for the individual, only to see your home, where you feel comfortable, being totally demolished and trashed. For some, that is perhaps the hardest thing to deal with, that you can not move back to your home in maybe years. As you probably have understood or realized, the consequences of a tsunami is outrageous, so some time in the future there has to be a warning-system that works, not perfectly, but it has to be more accurate then the ones we have today, so we can predict a tsunami at an earlier stage than seeing the wave from the shore, when it is already too late. One thing that could work, but so far only in theory, is to place out sensors in vulnerable areas in the ocean, which can sense an upcoming tsunami, hours before it may hit land.
A warning-system like this may save millions of lives, and money for that sake, if tsunamis keep threatening man kind. That we can not know for sure, but it is most likely going to happen, whether we want it or not. But as it is today, there is hardly anything we can do to stop these monsters, we can only wait for them to come, hoping that we can evacuate in time.

Källor:

Nationalencyklopedins officiella hemsida. [Elektronisk]. Tillgänglig: http://www.ne.se/jsp/search/article.jsp?i_art_id=332547 [2006-03-21]

, S. Wikipedia. [Elektronisk]. Tillgänglig: http://www.wikipedia.org [2006-03-16]

NASA''s public observatorium. [Elektronisk]. Tillgänglig: hhtp://observe.arc.nasa.gov [2006-03-21]

Caruso, K. Personlig hemsida. [Elektronisk]. Tillgänglig: http://www.tsunamis.com [2006-03-28]

Nationalencyklopedin is a source that I know I can trust, because it is a very famous dictionary and everything written there is based on facts and actual events. Wikipedia is usually as reliable, but on this occasion it is. Usually, everyone who wants can edit and change a text there, but when it came to tsunamis, that were blocked. You could not edit the facts, it was clearly stated at the top o...