What is a tsunami?
A
tsunami is a series of ocean waves that sends surges of water,
sometimes reaching heights of over 100 feet (30.5 meters), onto land.
These walls of water can cause widespread destruction when they crash
ashore.
Tsunamis
race across the sea at up to 500 miles (805 kilometers) an hour—about
as fast as a jet airplane. At that pace they can cross the entire
expanse of the Pacific Ocean in less than a day. And their long
wavelengths mean they lose very little energy along the way.
In
deep ocean, tsunami waves may appear only a foot or so high. But as
they approach shoreline and enter shallower water they slow down and
begin to grow in energy and height. The tops of the waves move faster
than their bottoms do, which causes them to rise precipitously.
What
causes a tsunami?
These
awe-inspiring waves are typically caused by large, undersea
earthquakes at tectonic plate boundaries. When the ocean floor at a
plate boundary rises or falls suddenly it displaces the water above
it and launches the rolling waves that will become a tsunami.
Most
tsunamis, about 80 percent, happen within the Pacific Ocean’s “Ring
of Fire,” a geologically active area where tectonic shifts make
volcanoes and earthquakes common.
Tsunamis
may also be caused by underwater landslides or volcanic eruptions.
They may even be launched, as they frequently were in Earth’s
ancient past, by the impact of a large meteorite plunging into an
ocean.
Effects
Being a giant,
fast-moving wave carrying an enormous amount of energy, it doesn’t
come as a surprise that the effects of a tsunami are devastating,
instantaneous and long-lasting. However, the severity of a tsunami’s
effects depends on a number of factors, for example the magnitude of
the phenomenon which originated the tsunami in the first place: while
small tsunamis are nearly undetectable, larger tsunamis sweep away
everything in their path and have effects which are often
irreversible. The impact of this natural disaster brings on
destruction and damages, death, injuries, diseases, financial loss,
psychological problems, among others.
Destruction
and damage
The impact of the waves knocks down infrastructure, damages property and permanently alters the landscape (by severely eroding the foundations of the coastline), leaving behind a mass of solid waste and debris, as well as toxic substances and industrial raw materials –leaked as a result of property damage-, that is almost impossible to clean up, which causes all kind of problems in the long run. Severe flooding plus the initial impact gravely damages sewer systems, water supplies and soil, which becomes salinized from sea water and debris.
If the tsunami hits poor and less-developed countries which are not built strongly enough to withstand such a natural disaster, the consequences are catastrophic.
The impact of the waves knocks down infrastructure, damages property and permanently alters the landscape (by severely eroding the foundations of the coastline), leaving behind a mass of solid waste and debris, as well as toxic substances and industrial raw materials –leaked as a result of property damage-, that is almost impossible to clean up, which causes all kind of problems in the long run. Severe flooding plus the initial impact gravely damages sewer systems, water supplies and soil, which becomes salinized from sea water and debris.
If the tsunami hits poor and less-developed countries which are not built strongly enough to withstand such a natural disaster, the consequences are catastrophic.
Death and
Injuries
Because there is very little warning before a tsunami hits, coastal residents do not have much time to escape, which leads to massive loss of human life either by drowning, being hit by collapsing buildings, electrocution, fires, explosions or diseases, and many people are reported missing. Animals and vegetation are also washed away.
Because there is very little warning before a tsunami hits, coastal residents do not have much time to escape, which leads to massive loss of human life either by drowning, being hit by collapsing buildings, electrocution, fires, explosions or diseases, and many people are reported missing. Animals and vegetation are also washed away.
Diseases
Tsunamis cause the area closest to the coast to flood, this leads to the outbreak and rapid spread of diseases such as malaria, which forms from the stagnant and contaminated water. Disease can also spread from dead bodies; this is why it is recommended to burn the dead instead of burying them. Often the damage induced to the sewage and fresh water supplies makes it more difficult for people to stay healthy and for diseases to be treated; therefore, an environment is created where more illnesses, infections and death are easily spread.
Tsunamis cause the area closest to the coast to flood, this leads to the outbreak and rapid spread of diseases such as malaria, which forms from the stagnant and contaminated water. Disease can also spread from dead bodies; this is why it is recommended to burn the dead instead of burying them. Often the damage induced to the sewage and fresh water supplies makes it more difficult for people to stay healthy and for diseases to be treated; therefore, an environment is created where more illnesses, infections and death are easily spread.
Financial
loss
When a tsunami happens, there is immediately massive cost, and the great need for financial and material assistance lingers for months –even years- after the disaster itself. The immense monetary cost of this situation covers the expenses for rescue teams, aid to the tsunami-hit area, clean up cost, etc. Specifically, the money goes to surveying and monitoring for infectious and water-transmitted diseases, diverting medical supplies, restoring normal primary health services and assisting the community to recover both, mentally and socially once the crisis has subsided. There is also loss of earnings in the local economy as well as future losses, since the damaged area will be so for a while.
When a tsunami happens, there is immediately massive cost, and the great need for financial and material assistance lingers for months –even years- after the disaster itself. The immense monetary cost of this situation covers the expenses for rescue teams, aid to the tsunami-hit area, clean up cost, etc. Specifically, the money goes to surveying and monitoring for infectious and water-transmitted diseases, diverting medical supplies, restoring normal primary health services and assisting the community to recover both, mentally and socially once the crisis has subsided. There is also loss of earnings in the local economy as well as future losses, since the damaged area will be so for a while.
Psychological
problems
Those who survived a tsunami are prone to suffer psychological problems after the event; these might continue for years or even their lifetime. The most common problem that victims present is the post traumatic stress disorder (PTSD), but they also may suffer from anxiety, grief and depression.
Those who survived a tsunami are prone to suffer psychological problems after the event; these might continue for years or even their lifetime. The most common problem that victims present is the post traumatic stress disorder (PTSD), but they also may suffer from anxiety, grief and depression.
Preventive
Measures
The
best defense against any tsunami is early warning that allows people
to seek higher ground. The Pacific Tsunami Warning System, a
coalition of 26 nations headquartered in Hawaii, maintains a web of
seismic equipment and water level gauges to identify tsunamis at sea.
Similar systems are proposed to protect coastal areas worldwide.
A
tsunami’s trough, the low point beneath the wave’s crest, often
reaches shore first. When it does, it produces a vacuum effect that
sucks coastal water seaward and exposes harbor and sea floors. This
retreating of sea water is an important warning sign of a tsunami,
because the wave’s crest and its enormous volume of water typically
hit shore five minutes or so later. Recognizing this phenomenon can
save lives.
A
tsunami is usually composed of a series of waves, called a wave
train, so its destructive force may be compounded as successive waves
reach shore. People experiencing a tsunami should remember that the
danger may not have passed with the first wave and should await
official word that it is safe to return to vulnerable locations.
Tsunamis
can wreak havoc on coastal populations and landscapes. The December
26, 2004, tsunami in the Indian Ocean claimed some 150,000 lives and
cleared the landscape on millions of acres of oceanfront terrain.
Here are some measures you can take to avoid trouble if you're caught
in a tsunami.
Safety
Tips
When
in coastal areas, stay alert for tsunami warnings.
Know
the warning signs of a tsunami: rapidly rising or falling coastal
waters and rumblings of an offshore earthquake.
Never
stay near shore to watch a tsunami come in.
A
tsunami is a series of waves. Do not return to an affected coastal
area until authorities say it is safe.
Sources and sites consulted
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