Megatsunami of the Canary Islands. what threat?
Researchers predict that a megatsunami, with waves almost a kilometer
high, could occur in the island from La Palma to the Canary Islands in the
near future. What will be the causes and the consequences?
What is the difference between a tsunami and a megatsunami?
One of the deadliest tsunamis in history is the one that occurred in the Indian
Ocean in 2004, following a tremor earth, with a magnitude of 9.2. He made more
than 250,000 victims and disappeared in 14 countries. The earthquake caused
waves up to 30 meters that swept over on the coasts of Indonesia, Sri Lanka,
Thailand and India and even some countries of East Africa.
The most recent example is the tsunami of 2011 in Japan. It occurred as a
result of a 9.0 magnitude earthquake in the Pacific. It has generated waves
up to 30 meters in some places and has made more than 18,000 dead and missing,
as well as estimated damage to 210 billion dollars and also caused the accident at
the Fukushima nuclear power plant, which is considered the most serious
nuclear disaster since Chernobyl. A tsunami is a series of very
high waves, up to 30 meters, that break on the coast after an
earthquake, landslide or eruption underwater.
While a tsunami usually produces waves up to 30 meters high, the
giant waves of a megatsunami can reach 300 meters and even a
kilometer high in some places. They can also spread in the ocean at the
same speed as an airliner, either 900 km / h.
The megatsunami is triggered by the landslide very large masses of rocks in the water,
following a volcanic eruption. This which creates a shock wave that spreads rapidly
in the water and devastates everything its passage.
The question is : Have there ever been
megatsunamis in the past? Over the last 50,000 years, there
have been several megatsunamis. As example, 8000 years ago, the eruption of
Etna in Italy caused waves of several hundreds of meters high that ravaged
much of the Mediterranean coast. In more recent times, an earthquake
with a magnitude of 8.3 has occurred in the Lituya Bay in Alaska in 1958. Part
of more than 40 million cubic meters of The side of the mountain broke off and
ended up in the water of the bay. He begot a tsunami, with waves over 525
meters high, which swept and shaved the vegetation up to a height of 525
meters. These are the highest waves never registered so far.
As this megatsunami only happened in an isolated and uncrowded bay, he
only made a few casualties among the sinners.
What kind of phenomena is it possible in a near future elsewhere,
in more populated places? The Cumbre Vieja, an active volcano on the island
of La Palma, the most western of the islands Canaries located off the coast of Morocco
is considered by researchers as the most likely candidate who can cause
a big megatsunami. Simon Day one of they showed in an article published in the
journal “Geophysical Research” in 2001 that a collapse of part of the island would most
likely occur during the next eruptions. The shape of this volcano is a ridge
along which there are several craters. During the last eruption in 1949,
after a series of earthquakes, half Western of this volcano has slipped
four meters towards the Atlantic Ocean. A fault of more than two kilometers
formed all along the ridge. Scientists believe that the west flank of
the volcano could fall into the ocean. If this happens, more than 500 cubic km of
rocks and earth will spill into the ocean by creating a huge megatsunami that
would ravage much of the Atlantic coast North.
A new eruption of the volcano could therefore be catastrophic and cause several
million deaths in several countries in Africa, Western Europe and the Americas.
What is the scenario of the disaster? If part of the island of La Palma collapses into
the ocean, we would witness a real scenario According to an article
published in 2001, researchers have shown with computer simulations that in
case of collapse of a part of the volcano of Cumbre Vieja, a large wave of almost
1 kilometer high would take birth near from the island of La Palma. It would cause
a giant tsunami that would devastate all coasts of the Atlantic Ocean. The collapse
of this volcano seems only a question of time.
The article by researchers Steven N. Ward and Simon Day establishes a scenario to
track the size and progression of enormous waves that would produce the collapse of
the flank of the volcano of the island of La Palma. The collapse will produce a colossal wave of
a size between 900 meters and 1 kilometer. To give an idea. It would be three times
the size of the Eiffel Tower. Waves would then progress very quickly and
in all directions through everything The Atlantic Ocean.
According to the scenario developed by the researchers, the future eruption of the Cumbre Vieja, would
throw more than 500 cubic kilometers of rocks and almost half of the island of La Palma
in the ocean. The waves generated by this megatsunami would cross the entire Atlantic
in less than 9 hours, ie, at the same speed as an airliner and would devastate everything
on their passes. The Canary Islands and West Africa would certainly suffer
the most serious consequences. According to the simulations, the Moroccan
coasts should receive waves of 150 meters, by comparison, the Indonesian coast
during the 2004 tsunami, received only waves 30 meters high.
The height of the waves when arriving on The coasts of Spain and Portugal should be
around 40 meters. The coasts of Great Britain would receive waves of nearly 8 meters.
The megatsunami would travel across the Atlantic at the speed of an airliner and would reach
the shores of North America and America South after 8 to 9 hours. They would lose
a lot of their height but would not lose not their destructive power. Indeed
like at a game billiards or each ball transmits its energy to the other by pushing
it further, each particle of water transmits his energy to the next. The megatsunami
will lose some of its energy while crossing the Atlantic, but will certainly cause
unimaginable damage when arriving in overpopulated cities like New York.
US odds would receive waves which can reach 25 meters. Even
having been warned for 8 hours, it is unlikely that the authorities could
evacuate the entire population of the cities coastal in such a short time.
Several series of waves would break on the coast and would go
up to 20 kilometers inland. To better understand the magnitude and severity
of the anticipated damage from the megatunami of La Palma, comparing with the tsunamis of
Japan from 2011 and Indonesia from 2004. Japan’s 2011 tsunami spawned waves
of 30 meters approaching the coast. It is considered, with these 285 billion
dollars as the natural disaster the most expensive in the history of mankind.
The 2004 Indonesia tsunami, with these 250,000 dead and gone is considered
one of the deadliest disasters Of the history. However, the waves of
this tsunami were only 20 meters high. Just imagine the damage that can cause
waves of 900 meters to the islands Canaries and 150 meters to their arrivals
on the coasts of North Africa and Europe from West.
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