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TSUNAMI: A tsunami (plural: tsunamis or tsunami; from Japanese: , lit. "harbour wave";[1] English
Tsunami waves do not resemble normal sea waves, because their wavelength is far longer. R
The Greek historian Thucydides suggested in his late 5th century BC, History of the Peloponn
CHARACTER
ISTIC:
Tsunamis cause damage by two mechanisms:
While everyday wind waves have a wavelength (from crest to crest) of about 100 metres (330
The reason for the Japanese name "harbour wave" is that sometimes a village's fishermen w
As the tsunami approaches the coast and the waters become shallow, wave shoaling compre
When the tsunami's wave peak reaches the shore, the resulting temporary rise in sea level is
About 80% of tsunamis occur in the Pacific Ocean, but they are possible wherever there are l
A tsunami (Japanese for "harbour wave") is series of huge ocean wave
On January 26, 1700 one of the world's largest earthquakes occurred along the west coast of North Amer
In the twentieth century, 27 people were killed on November 18, 1929 in the tsunami that struck the Burin
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, lit. "harbour wave";[1] English pronunciation: /sun mi/ soo-NAH-mee or /tsun mi/ tsoo-NAH-mee[2]) is
their wavelength is far longer. Rather than appearing as a breaking wave, a tsunami may instead initially resemble a
tury BC, History of the Peloponnesian War, that tsunamis were related to submarine earthquakes,[5][6] but the unde
o mechanisms: the smashing force of a wall of water trave
crest) of about 100 metres (330 ft) and a height of roughly 2 metres (6.6 ft), a tsunami in the deep ocean has a much
metimes a village's fishermen would sail out, and encounter no unusual waves while out at sea fishing, and come bac
shallow, wave shoaling compresses the wave and its speed decreases below 80 kilometres per hour (50 mph). Its w
ng temporary rise in sea level is termed run up. Run up is measured in metres above a reference sea level.[26] A larg
re possible wherever there are large bodies of water, including lakes. They are caused by earthquakes, landslides, vo
s of huge ocean waves caused by a rapid, large-scale disturbance of the sea
ng the west coast of North America and created a tsunami which completely destroyed the winter village of the Pache
he tsunami that struck the Burin Peninsula of Newfoundland. This tsunami was caused by a large submarine slump a
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n mi/ tsoo-NAH-mee[2]) is a series of water waves caused by the displacement of a large volume of a body of w
may instead initially resemble a rapidly rising tide, and for this reason they are often referred to as tidal waves. Tsuna
earthquakes,[5][6] but the understanding of a tsunami's nature remained slim until the 20th century and much remain
all of water travelling at high speed, and the destructive pow
mi in the deep ocean has a much larger wavelength of up to 200 kilometres (120 mi). Such a wave travels at well over
out at sea fishing, and come back to land to find their village devastated by a huge wave.
metres per hour (50 mph). Its wavelength diminishes to less than 20 kilometres (12 mi) and its amplitude grows enor
a reference sea level.[26] A large tsunami may feature multiple waves arriving over a period of hours, with significan
d by earthquakes, landslides, volcanic explosions, glacier calvings, and bolides.
sturbance of the sea water. Tsunamis can be caused by submarine volcanic er
d the winter village of the Pachena Bay people with no survivors. These events are recorded in the oral traditions of t
d by a large submarine slump along the continental slope triggered by the magnitude 7.2 earthquake that struck app
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f a large volume of a body of water, generally an ocean or a large lake. Earthquakes, volcanic eruptions and other un
eferred to as tidal waves. Tsunamis generally consist of a series of waves with periods ranging from minutes to hours
e 20th century and much remains unknown[clarify]. Major areas of current research include trying to determine why s
e destructive power of a large volume of water draining off t
Such a wave travels at well over 800 kilometres per hour (500 mph), but owing to the enormous wavelength the wave
mi) and its amplitude grows enormously. Since the wave still has the same very long period, the tsunami may take mi
period of hours, with significant time between the wave crests. The first wave to reach the shore may not have the h
submarine volcanic eruptions, submarine landslides, meteor impact, and majo
corded in the oral traditions of the First Nations people on Vancouver Island. There is evidence of repeated tsunamis
7.2 earthquake that struck approximately 250 km to the south along the edge of the Laurentian Slope.
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volcanic eruptions and other underwater explosions (including detonations of underwater nuclear devices), landslide
s ranging from minutes to hours, arriving in a so-called "wave train".[4] Wave heights of tens of metres can be gener
clude trying to determine why some large earthquakes do not generate tsunamis while other smaller ones do; trying
ater draining off the land and carrying a large amount of deb
enormous wavelength the wave oscillation at any given point takes 20 or 30 minutes to complete a cycle and has an
eriod, the tsunami may take minutes to reach full height. Except for the very largest tsunamis, the approaching wave
h the shore may not have the highest run up. [27]
eor impact, and major earthquakes occuring beneath the seabed causing larg
evidence of repeated tsunamis inundating our west coast following giant megathrust earthquakes in the Cascadia s
Laurentian Slope.
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water nuclear devices), landslides, glacier calvings, meteorite impacts and other disturbances above or below water a
of tens of metres can be generated by large events. Although the impact of tsunamis is limited to coastal areas, their
e other smaller ones do; trying to accurately forecast the passage of tsunamis across the oceans; and also to foreca
ge amount of debris with it, even with waves that do not loo
o complete a cycle and has an amplitude of only about 1 metre (3.3 ft). [25] This makes tsunamis difficult to detect o
sunamis, the approaching wave does not break, but rather appears like a fast-moving tidal bore.[26] Open bays and
seabed causing large vertical movements. In deep water, tsunami waves are
earthquakes in the Cascadia seismic zone.
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rbances above or below water all have the potential to generate a tsunami.[3]
is limited to coastal areas, their destructive power can be enormous and they can affect entire ocean basins; the 200
s the oceans; and also to forecast how tsunami waves would interact with specific shorelines.
s that do not look large.
es tsunamis difficult to detect over deep water, where ships are unable to feel their passage.
tidal bore.[26] Open bays and coastlines adjacent to very deep water may shape the tsunami further into a step-like
r, tsunami waves are less than a metre high, but they can travel at speeds exc
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ect entire ocean basins; the 2004 Indian Ocean tsunami was among the deadliest natural disasters in human history
tsunami further into a step-like wave with a steep-breaking front.
n travel at speeds exceeding 800 kilometres per hour and can easily cross an
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tural disasters in human history with over 230,000 people killed in 14 countries bordering the Indian Ocean.
d can easily cross an entire ocean basin. When they reach shallow water or na
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ering the Indian Ocean.
h shallow water or narrow inlets the waves slow down and the height can buil
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nd the height can build into a wall of water which causes devastation on the sh
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devastation on the shore.
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