Series of water waves caused by the displacement of a large volume of a body of water
"Sunami" redirects here. For the hardcore punk band, see
Sunami (band)
.
A
tsunami
(
(t)soo-
NAH
-mee, (t)suu-
;
[1]
[2]
[3]
[4]
from
Japanese
:
津波
,
lit.
'harbour wave',
[5]
pronounced
[ts?nami]
) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a
large lake
.
Earthquakes
,
volcanic eruptions
and other
underwater explosions
(including detonations,
landslides
,
glacier calvings
,
meteorite impacts
and other disturbances) above or below water all have the potential to generate a tsunami.
[6]
Unlike normal
ocean waves, which are generated by wind
, or
tides
, which are in turn generated by the
gravitational pull
of the
Moon
and the
Sun
, a tsunami is generated by the displacement of water from a large event.
Tsunami waves do not resemble normal undersea currents or
sea waves
because their
wavelength
is far longer.
[7]
Rather than appearing as a
breaking wave
, a tsunami may instead initially resemble a rapidly rising
tide
.
[8]
For this reason, it is often referred to as a
tidal wave
,
[9]
although this usage is not favoured by the scientific community because it might give the false impression of a causal relationship between tides and tsunamis.
[10]
Tsunamis generally consist of a series of waves, with
periods
ranging from minutes to hours, arriving in a so-called "
wave train
".
[11]
Wave heights of tens of metres can be generated by large events. Although the impact of tsunamis is limited to coastal areas, their destructive power can be enormous, and they can affect entire ocean basins. The
2004 Indian Ocean tsunami
was among the deadliest natural disasters in human history, with at least 230,000 people killed or missing in 14 countries bordering the
Indian Ocean
.
The
Ancient Greek
historian
Thucydides
suggested in his 5th century BC
History of the Peloponnesian War
that tsunamis were related to
submarine earthquakes
,
[12]
[13]
but the understanding of tsunamis remained slim until the 20th century, and much remains unknown. Major areas of current research include determining why some large earthquakes do not generate tsunamis while other smaller ones do. This ongoing research is designed to help accurately forecast the passage of tsunamis across oceans as well as how tsunami waves interact with shorelines.
Terminology
Tsunami
The term "tsunami" is a
borrowing
from the Japanese
tsunami
津波
, meaning "harbour wave." For the plural, one can either follow ordinary English practice and add an
s
, or use an invariable plural as in the Japanese.
[14]
Some English speakers alter the word's initial
/
ts
/
to an
/
s
/
by dropping the "t," since English does not natively permit
/ts/
at the beginning of words, though the original Japanese pronunciation is
/ts/
. The term has become commonly accepted in English, although its literal Japanese meaning is not necessarily descriptive of the waves, which do not occur only in harbours.
Tidal wave
Tsunamis are sometimes referred to as
tidal waves
.
[15]
This once-popular term derives from the most common appearance of a tsunami, which is that of an extraordinarily high
tidal bore
. Tsunamis and tides both produce waves of water that move inland, but in the case of a tsunami, the inland movement of water may be much greater, giving the impression of an incredibly high and forceful tide. In recent years, the term "tidal wave" has fallen out of favour, especially in the scientific community, because the causes of tsunamis have nothing to do with those of
tides
, which are produced by the gravitational pull of the moon and sun rather than the displacement of water. Although the meanings of "tidal" include "resembling"
[16]
or "having the form or character of"
[17]
tides, use of the term
tidal wave
is discouraged by geologists and oceanographers.
A 1969 episode of the TV crime show
Hawaii Five-O
entitled "Forty Feet High and It Kills!" used the terms "tsunami" and "tidal wave" interchangeably.
[18]
Seismic sea wave
The term
seismic sea wave
is also used to refer to the phenomenon because the waves most often are generated by
seismic
activity such as earthquakes.
[19]
Prior to the rise of the use of the term
tsunami
in English, scientists generally encouraged the use of the term
seismic sea wave
rather than
tidal wave
. However, like
tidal wave
,
seismic sea wave
is not a completely accurate term, as forces other than earthquakes?including underwater
landslides
, volcanic eruptions, underwater explosions, land or ice
slumping
into the ocean,
meteorite
impacts, and the weather when the atmospheric pressure changes very rapidly?can generate such waves by displacing water.
[20]
[21]
Other terms
The use of the term
tsunami
for waves created by landslides entering bodies of water has become internationally widespread in both scientific and popular literature, although such waves are distinct in origin from large waves generated by earthquakes. This distinction sometimes leads to the use of other terms for landslide-generated waves, including
landslide-triggered tsunami
,
displacement wave
,
non-seismic wave
,
impact wave
, and, simply,
giant wave
.
[22]
History
While Japan may have the longest
recorded history
of tsunamis,
[23]
[
better source needed
]
the sheer destruction caused by the
2004 Indian Ocean earthquake and tsunami
event mark it as the most devastating of its kind in modern times, killing around 230,000 people.
[24]
The
Sumatran
region is also accustomed to tsunamis, with earthquakes of varying magnitudes regularly occurring off the coast of the island.
[25]
Tsunamis are an often underestimated hazard in the
Mediterranean Sea
and parts of Europe. Of historical and current (with regard to risk assumptions) importance are the
1755 Lisbon earthquake and tsunami
(which was caused by the
Azores?Gibraltar Transform Fault
), the
1783 Calabrian earthquakes
, each causing several tens of thousands of deaths and the
1908 Messina earthquake
and tsunami. The tsunami claimed more than 123,000 lives in Sicily and Calabria and is among the deadliest natural disasters in modern Europe. The
Storegga Slide
in the Norwegian Sea and some examples of
tsunamis affecting the British Isles
refer to landslide and
meteotsunamis
, predominantly and less to earthquake-induced waves.
As early as 426 BC
the
Greek
historian
Thucydides
inquired in his book
History of the Peloponnesian War
about the causes of tsunami, and was the first to argue that ocean earthquakes must be the cause.
[12]
[13]
The oldest human record of a tsunami dates back to
479 BC
, in the Greek colony of
Potidaea
, thought to be triggered by an earthquake. The tsunami may have saved the colony from an invasion by the
Achaemenid Empire
.
[13]
The cause, in my opinion, of this phenomenon must be sought in the earthquake. At the point where its shock has been the most violent the sea is driven back, and suddenly recoiling with redoubled force, causes the inundation. Without an earthquake I do not see how such an accident could happen.
[26]
The
Roman
historian
Ammianus Marcellinus
(
Res Gestae
26.10.15?19) described the typical sequence of a tsunami, including an incipient earthquake, the sudden retreat of the sea and a following gigantic wave, after the
365 AD tsunami
devastated
Alexandria
.
[27]
[28]
Causes
The principal generation mechanism of a tsunami is the displacement of a substantial volume of water or perturbation of the sea.
[29]
This displacement of water is usually caused by earthquakes,
[30]
[31]
[32]
but can also be attributed to landslides, volcanic eruptions, glacier calvings or more rarely by meteorites and nuclear tests.
[33]
[34]
However, the possibility of a meteorite causing a tsunami is debated.
[35]
Seismicity
Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of earthquake that are associated with the Earth's crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position.
[36]
More specifically, a tsunami can be generated when
thrust faults
associated with
convergent
or destructive
plate boundaries
move abruptly, resulting in water displacement, owing to the vertical component of movement involved. Movement on
normal (extensional) faults
can also cause displacement of the seabed, but only the largest of such events (typically related to flexure in the
outer trench swell
) cause enough displacement to give rise to a significant tsunami, such as the
1977 Sumba
and
1933 Sanriku
events.
[37]
[38]
Tsunamis have a small wave height offshore, and a very long
wavelength
(often hundreds of kilometres long, whereas normal ocean waves have a wavelength of only 30 or 40 metres),
[39]
which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 millimetres (12 in) above the normal sea surface. They grow in height when they reach shallower water, in a
wave shoaling
process described below. A tsunami can occur in any tidal state and even at low tide can still inundate coastal areas.
On April 1, 1946, the 8.6 M
w
Aleutian Islands earthquake
occurred with a maximum
Mercalli intensity
of VI (
Strong
). It generated a tsunami which inundated
Hilo
on the island of Hawaii with a 14-metre high (46 ft) surge. Between 165 and 173 were killed. The area where the earthquake occurred is where the
Pacific Ocean
floor is
subducting
(or being pushed downwards) under Alaska.
Examples of tsunamis originating at locations away from convergent boundaries include
Storegga
about 8,000 years ago,
Grand Banks
in 1929, and
Papua New Guinea
in 1998 (Tappin, 2001). The Grand Banks and Papua New Guinea tsunamis came from earthquakes which destabilised sediments, causing them to flow into the ocean and generate a tsunami. They dissipated before travelling transoceanic distances.
The cause of the Storegga sediment failure is unknown. Possibilities include an overloading of the sediments, an earthquake or a release of gas hydrates (methane etc.).
The
1960 Valdivia earthquake
(
M
w
9.5),
1964 Alaska earthquake
(
M
w
9.2),
2004 Indian Ocean earthquake
(
M
w
9.2), and
2011 T?hoku earthquake
(
M
w
9.0) are recent examples of powerful
megathrust earthquakes
that generated tsunamis (known as
teletsunamis
) that can cross entire oceans. Smaller (
M
w
4.2) earthquakes in Japan can trigger tsunamis (called local and regional tsunamis) that can devastate stretches of coastline, but can do so in only a few minutes at a time.
Landslides
The
Tauredunum event
was a large tsunami on
Lake Geneva
in 563 CE, caused by sedimentary deposits destabilised by a landslide.
In the 1950s, it was discovered that tsunamis larger than had previously been believed possible can be caused by giant
submarine landslides
. These large volumes of rapidly displaced water transfer energy at a faster rate than the water can absorb. Their existence was confirmed in 1958, when a giant landslide in
Lituya Bay
, Alaska, caused the highest wave ever recorded, which had a height of 524 metres (1,719 ft).
[40]
The wave did not travel far as it struck land almost immediately. The wave struck three boats?each with two people aboard?anchored in the bay. One boat rode out the wave, but the wave sank the other two, killing both people aboard one of them.
[41]
[42]
[43]
Another landslide-tsunami event occurred in 1963 when a massive landslide from
Monte Toc
entered the reservoir behind the
Vajont Dam
in Italy. The resulting wave surged over the 262-metre (860 ft)-high dam by 250 metres (820 ft) and destroyed several towns. Around 2,000 people died.
[44]
[45]
Scientists named these waves
megatsunamis
.
Some geologists claim that large landslides from volcanic islands, e.g.
Cumbre Vieja
on
La Palma
(
Cumbre Vieja tsunami hazard
) in the
Canary Islands
, may be able to generate megatsunamis that can cross oceans, but this is disputed by many others.
In general, landslides generate displacements mainly in the shallower parts of the coastline, and there is conjecture about the nature of large landslides that enter the water. This has been shown to subsequently affect water in enclosed bays and lakes, but a landslide large enough to cause a transoceanic tsunami has not occurred within recorded history. Susceptible locations are believed to be the
Big Island
of
Hawaii
,
Fogo
in the
Cape Verde Islands
,
La Reunion
in the
Indian Ocean
, and
Cumbre Vieja
on the island of
La Palma
in the
Canary Islands
; along with other volcanic ocean islands. This is because large masses of relatively unconsolidated volcanic material occurs on the flanks and in some cases detachment planes are believed to be developing. However, there is growing controversy about how dangerous these slopes actually are.
[46]
Volcanic eruptions
Other than by landslides or
sector collapse
, volcanoes may be able to generate waves by
pyroclastic flow
submergence, caldera collapse, or underwater explosions.
[47]
Tsunamis have been triggered by a number of volcanic eruptions, including the
1883 eruption of Krakatoa
, and the
2022 Hunga Tonga?Hunga Ha'apai eruption
. Over 20% of all fatalities caused by volcanism during the past 250 years are estimated to have been caused by
volcanogenic
tsunamis.
[48]
Debate has persisted over the origins and source mechanisms of these types of tsunamis, such as those generated by Krakatoa in 1883,
[48]
and they remain lesser understood than their seismic relatives. This poses a large problem of awareness and preparedness, as exemplified by the eruption and collapse of
Anak Krakatoa in 2018
, which killed 426 and injured thousands when no warning was available.
It is still regarded that lateral landslides and ocean-entering pyroclastic currents are most likely to generate the largest and most hazardous waves from volcanism;
[49]
however, field investigation of the
Tongan event
, as well as developments in numerical modelling methods, currently aim to expand the understanding of the other source mechanisms.
[50]
[51]
Meteorological
Some
meteorological
conditions, especially rapid changes in barometric pressure, as seen with the passing of a front, can displace bodies of water enough to cause trains of waves with wavelengths. These are comparable to seismic tsunamis, but usually with lower energies. Essentially, they are dynamically equivalent to seismic tsunamis, the only differences being 1) that meteotsunamis lack the transoceanic reach of significant seismic tsunamis, and 2) that the force that displaces the water is sustained over some length of time such that meteotsunamis cannot be modelled as having been caused instantaneously. In spite of their lower energies, on shorelines where they can be amplified by resonance, they are sometimes powerful enough to cause localised damage and potential for loss of life. They have been documented in many places, including the Great Lakes, the Aegean Sea, the English Channel, and the Balearic Islands, where they are common enough to have a local name,
rissaga
. In Sicily they are called
marubbio
and in Nagasaki Bay, they are called
abiki
. Some examples of destructive meteotsunamis include 31 March 1979 at Nagasaki and 15 June 2006 at Menorca, the latter causing damage in the tens of millions of euros.
[52]
Meteotsunamis should not be confused with
storm surges
, which are local increases in sea level associated with the low barometric pressure of passing tropical cyclones, nor should they be confused with setup, the temporary local raising of sea level caused by strong on-shore winds. Storm surges and setup are also dangerous causes of
coastal flooding
in severe weather but their dynamics are completely unrelated to tsunami waves.
[52]
They are unable to propagate beyond their sources, as waves do.
Human-made or triggered tsunamis
The accidental
Halifax Explosion
in 1917 triggered an 18-metre high tsunami in the harbour.
There have been studies of the potential of the induction of and at least one actual attempt to create tsunami waves as a
tectonic weapon
.
In World War II, the
New Zealand Military Forces
initiated
Project Seal
, which attempted to create small tsunamis with explosives in the area of today's
Shakespear Regional Park
; the attempt failed.
[53]
There has been considerable speculation on the possibility of using
nuclear weapons
to cause tsunamis near an enemy coastline. Even during
World War II
consideration of the idea using conventional explosives was explored. Nuclear testing in the
Pacific Proving Ground
by the United States seemed to generate poor results.
Operation Crossroads
fired two 20 kilotonnes of TNT (84 TJ) bombs, one in the air and one underwater, above and below the shallow (50 m (160 ft)) waters of the
Bikini Atoll
lagoon. Fired about 6 km (3.7 mi) from the nearest island, the waves there were no higher than 3?4 m (9.8?13.1 ft) upon reaching the shoreline. Other underwater tests, mainly
Hardtack I
/Wahoo
(deep water) and
Hardtack I/Umbrella
(shallow water) confirmed the results. Analysis of the effects of
shallow
and
deep underwater explosions
indicate that the energy of the explosions does not easily generate the kind of deep, all-ocean waveforms which are tsunamis; most of the energy creates steam, causes vertical fountains above the water, and creates compressional waveforms.
[54]
Tsunamis are hallmarked by permanent large vertical displacements of very large volumes of water which do not occur in explosions.
Characteristics
Tsunamis are caused by earthquakes, landslides, volcanic explosions, glacier calvings, and
bolides
. They cause damage by two mechanisms: the smashing force of a wall of water travelling at high speed, and the destructive power of a large volume of water draining off the land and carrying a large amount of debris with it, even with waves that do not appear to be large.
While everyday
wind waves
have a
wavelength
(from crest to 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 larger wavelength of up to 200 kilometres (120 mi). Such a wave travels at well over 800 kilometres per hour (500 mph), but owing to the enormous wavelength the wave oscillation at any given point takes 20 or 30 minutes to complete a cycle and has an amplitude of only about 1 metre (3.3 ft).
[55]
This makes tsunamis difficult to detect over deep water, where ships are unable to feel their passage.
The velocity of a tsunami can be calculated by obtaining the square root of the depth of the water in metres multiplied by the acceleration due to gravity (approximated to 10 m/s
2
). For example, if the Pacific Ocean is considered to have a depth of 5000 metres, the velocity of a tsunami would be
√
5000 × 10
=
√
50000
? 224 metres per second (730 ft/s), which equates to a speed of about 806 kilometres per hour (501 mph). This is the formula used for calculating the velocity of
shallow-water
waves. Even the deep ocean is shallow in this sense because a tsunami wave is so long (horizontally from crest to crest) by comparison.
The reason for the Japanese name "harbour wave" is that sometimes a village's
fishermen
would sail out, and encounter no unusual waves while out at sea fishing, and come back to land to find their village devastated by a huge wave.
As the tsunami approaches the coast and the waters become shallow,
wave shoaling
compresses the wave and its speed decreases below 80 kilometres per hour (50 mph). Its wavelength diminishes to less than 20 kilometres (12 mi) and its amplitude grows enormously?in accord with
Green's law
. Since the wave still has the same very long
period
, the tsunami may take minutes to reach full height. Except for the very largest tsunamis, the approaching wave does not
break
, but rather appears like a fast-moving
tidal bore
.
[56]
Open bays and coastlines adjacent to very deep water may shape the tsunami further into a step-like wave with a steep-breaking front.
When the tsunami's wave peak reaches the shore, the resulting temporary rise in sea level is termed
run up
. Run up is measured in metres above a reference sea level.
[56]
A large tsunami may feature multiple waves arriving over a period of hours, with significant time between the wave crests. The first wave to reach the shore may not have the highest run-up.
[57]
About 80% of tsunamis occur in the Pacific Ocean, but they are possible wherever there are large bodies of water, including lakes. However, tsunami interactions with shorelines and the seafloor topography are extremely complex, which leaves some countries more vulnerable than others. For example, the Pacific coasts of the United States and Mexico lie adjacent to each other, but the United States has recorded ten tsunamis in the region since 1788, while Mexico has recorded twenty-five since 1732.
[58]
[59]
Similarly, Japan has had more than a hundred tsunamis in recorded history, while the neighbouring island of Taiwan has registered only two, in 1781 and 1867.
[60]
[61]
Drawback
All
waves
have a positive and negative peak; that is, a ridge and a trough. In the case of a propagating wave like a tsunami, either may be the first to arrive. If the first part to arrive at the shore is the ridge, a massive breaking wave or sudden flooding will be the first effect noticed on land. However, if the first part to arrive is a trough, a drawback will occur as the shoreline recedes dramatically, exposing normally submerged areas. The drawback can exceed hundreds of metres, and people unaware of the danger sometimes remain near the shore to satisfy their curiosity or to collect fish from the exposed seabed.
A typical wave period for a damaging tsunami is about twelve minutes. Thus, the sea recedes in the drawback phase, with areas well below sea level exposed after three minutes. For the next six minutes, the wave trough builds into a ridge which may flood the coast, and destruction ensues. During the next six minutes, the wave changes from a ridge to a trough, and the flood waters recede in a second drawback. Victims and debris may be swept into the ocean. The process repeats with succeeding waves.
Scales of intensity and magnitude
As with earthquakes, several attempts have been made to set up scales of tsunami intensity or magnitude to allow comparison between different events.
[62]
Intensity scales
The first scales used routinely to measure the intensity of tsunamis were the
Sieberg
-
Ambraseys
scale
(1962), used in the
Mediterranean Sea
and the
Imamura-Iida intensity scale
(1963), used in the Pacific Ocean. The latter scale was modified by Soloviev (1972), who calculated the tsunami intensity "
I
" according to the formula:
where
is the "tsunami height" in metres, averaged along the nearest coastline, with the tsunami height defined as the rise of the water level above the normal tidal level at the time of occurrence of the tsunami.
[63]
This scale, known as the
Soloviev-Imamura tsunami intensity scale
, is used in the global tsunami catalogues compiled by the NGDC/NOAA
[64]
and the Novosibirsk Tsunami Laboratory as the main parameter for the size of the tsunami.
This formula yields:
- I
= 2 for
= 2.8 metres
- I
= 3 for
= 5.5 metres
- I
= 4 for
= 11 metres
- I
= 5 for
= 22.5 metres
- etc.
In 2013, following the intensively studied tsunamis in 2004 and 2011, a new 12-point scale was proposed, the Integrated Tsunami Intensity Scale (ITIS-2012), intended to match as closely as possible to the modified
ESI2007
and
EMS
earthquake intensity scales.
[65]
[66]
Magnitude scales
The first scale that genuinely calculated a magnitude for a tsunami, rather than an intensity at a particular location was the ML scale proposed by Murty & Loomis based on the potential energy.
[62]
Difficulties in calculating the potential energy of the tsunami mean that this scale is rarely used. Abe introduced the
tsunami magnitude scale
, calculated from,
where
h
is the maximum tsunami-wave amplitude (in m) measured by a tide gauge at a distance
R
from the epicentre,
a
,
b
and
D
are constants used to make the M
t
scale match as closely as possible with the moment magnitude scale.
[67]
Tsunami heights
Several terms are used to describe the different characteristics of tsunami in terms of their height:
[68]
[69]
[70]
[71]
- Amplitude, Wave Height, or Tsunami Height: Refers to the height of a tsunami relative to the normal sea level at the time of the tsunami, which may be tidal High Water, or Low Water. It is different from the crest-to-trough height which is commonly used to measure other type of wave height.
[72]
- Run-up Height, or Inundation Height: The height reached by a tsunami on the ground above sea level, Maximum run-up height refers to the maximum height reached by water above sea level, which is sometimes reported as the maximum height reached by a tsunami.
- Flow Depth: Refers to the height of tsunami above ground, regardless of the height of the location or sea level.
- (Maximum) Water Level: Maximum height above sea level as seen from trace or water mark. Different from maximum run-up height in the sense that they are not necessarily water marks at inundation line/limit.
Warnings and predictions
Drawbacks can serve as a brief warning. People who observe drawback (many survivors report an accompanying sucking sound) can survive only if they immediately run for high ground or seek the upper floors of nearby buildings.
In 2004, ten-year-old
Tilly Smith
of
Surrey
, England, was on
Maikhao beach
in
Phuket
, Thailand with her parents and sister, and having learned about tsunamis recently in school, told her family that a tsunami might be imminent. Her parents warned others minutes before the wave arrived, saving dozens of lives. She credited her geography teacher, Andrew Kearney.
In the
2004 Indian Ocean tsunami
drawback was not reported on the African coast or any other east-facing coasts that it reached. This was because the initial wave moved downwards on the eastern side of the
megathrust
and upwards on the western side. The western pulse hit coastal Africa and other western areas.
A tsunami cannot be precisely predicted, even if the magnitude and location of an earthquake is known.
Geologists
,
oceanographers
, and
seismologists
analyse each earthquake and based on many factors may or may not issue a tsunami warning. However, there are some warning signs of an impending tsunami, and automated systems can provide warnings immediately after an earthquake in time to save lives. One of the most successful systems uses bottom pressure sensors, attached to buoys, which constantly monitor the pressure of the overlying water column.
Regions with a high tsunami risk typically use
tsunami warning systems
to warn the population before the wave reaches land. On the west coast of the United States, which is prone to tsunamis from the Pacific Ocean, warning signs indicate evacuation routes. In Japan, the populace is well-educated about earthquakes and tsunamis, and along Japanese shorelines, tsunami warning signs remind people of the natural hazards along with a network of warning sirens, typically at the top of the cliffs of surrounding hills.
[73]
The
Pacific Tsunami Warning System
is based in
Honolulu
,
Hawai?i
. It monitors Pacific Ocean seismic activity. A sufficiently large earthquake magnitude and other information triggers a tsunami warning. While the subduction zones around the Pacific are seismically active, not all earthquakes generate a tsunami. Computers assist in analysing the tsunami risk of every earthquake that occurs in the Pacific Ocean and the adjoining land masses.
As a direct result of the Indian Ocean tsunami, a re-appraisal of the tsunami threat for all coastal areas is being undertaken by national governments and the United Nations Disaster Mitigation Committee. A tsunami warning system is being installed in the Indian Ocean.
Computer models
can predict tsunami arrival, usually within minutes of the arrival time. Bottom pressure sensors can relay information in
real time
. Based on these pressure readings and other seismic information and the seafloor's shape (
bathymetry
) and coastal
topography
, the models estimate the amplitude and surge height of the approaching tsunami. All
Pacific Rim
countries collaborate in the Tsunami Warning System and most regularly practise evacuation and other procedures. In Japan, such preparation is mandatory for government, local authorities, emergency services and the population.
Along the United States west coast, in addition to sirens, warnings are sent on television and radio via the
National Weather Service
, using the
Emergency Alert System
.
Possible animal reaction
Some zoologists hypothesise that some animal species have an ability to sense subsonic
Rayleigh waves
from an earthquake or a tsunami. If correct, monitoring their behaviour could provide advance warning of earthquakes and tsunamis. However, the evidence is controversial and is not widely accepted. There are unsubstantiated claims about the
Lisbon quake
that some animals escaped to higher ground, while many other animals in the same areas drowned. The phenomenon was also noted by media sources in
Sri Lanka
in the
2004 Indian Ocean earthquake
.
[74]
[75]
It is possible that certain animals (e.g.,
elephants
) may have heard the sounds of the tsunami as it approached the coast. The elephants' reaction was to move away from the approaching noise. By contrast, some humans went to the shore to investigate and many drowned as a result.
Mitigation
In some tsunami-prone countries,
earthquake engineering
measures have been taken to reduce the damage caused onshore.
Japan
, where tsunami science and response measures first began following a
disaster in 1896
, has produced ever-more elaborate countermeasures and response plans.
[76]
The country has built many tsunami walls of up to 12 metres (39 ft) high to protect populated coastal areas. Other localities have built
floodgates
of up to 15.5 metres (51 ft) high and channels to redirect the water from an incoming tsunami. However, their effectiveness has been questioned, as tsunamis often overtop the barriers.
The
Fukushima Daiichi nuclear disaster
was directly triggered by the
2011 T?hoku earthquake and tsunami
, when waves exceeded the height of the plant's sea wall.
[77]
Iwate Prefecture
, which is an area at high risk from tsunami, had tsunami barriers walls (
Taro sea wall
) totalling 25 kilometres (16 mi) long at coastal towns. The 2011 tsunami toppled more than 50% of the walls and caused catastrophic damage.
[78]
The
Okushiri, Hokkaid? tsunami
, which struck within two to five minutes of the
earthquake on July 12, 1993
, created waves 30 metres (100 ft) tall?as high as a 10-storey building. The port town of
Aonae
was completely surrounded by a tsunami wall, but the waves washed right over the wall and destroyed all the wood-framed structures in the area. The wall may have succeeded in slowing down and moderating the height of the tsunami, but it did not prevent major destruction and loss of life.
[79]
See also
- ^
Wells, John C. (1990).
Longman pronunciation dictionary
. Harlow, England: Longman. p. 736.
ISBN
978-0-582-05383-0
.
Entry: "tsunami"
- ^
"tsunami"
.
Macmillan Dictionary
. Retrieved
2018-11-23
.
- ^
"tsunami"
.
Merriam-Webster.com Dictionary
. Retrieved
19 August
2019
.
- ^
"tsunami"
.
Longman Dictionary of Contemporary English
.
Longman
. Retrieved
19 August
2019
.
- ^
"Tsunami Terminology"
.
NOAA
. Archived from
the original
on 2011-02-25
. Retrieved
2010-07-15
.
- ^
Barbara Ferreira (April 17, 2011).
"When icebergs capsize, tsunamis may ensue"
.
Nature
. Archived from
the original
on 2011-11-04
. Retrieved
2011-04-27
.
- ^
"NASA Finds Japan Tsunami Waves Merged, Doubling Power"
.
Jet Propulsion Laboratory
. Retrieved
3 November
2016
.
- ^
"Tsunami 101"
. University of Washington
. Retrieved
1 December
2018
.
- ^
"Definition of Tidal Wave"
.
- ^
"What does "tsunami" mean?"
. Earth and Space Sciences, University of Washington
. Retrieved
1 December
2018
.
- ^
Fradin, Judith Bloom and Dennis Brindell (2008).
Witness to Disaster: Tsunamis
. Washington, D.C.:
National Geographic Society
. pp. 42?43. Archived from
the original
on 2012-04-06.
- ^
a
b
Thucydides
:
“A History of the Peloponnesian War”, 3.89.1?4
- ^
a
b
c
Smid, T. C. (April 1970).
'Tsunamis' in Greek Literature
. Vol. 17 (2nd ed.). pp. 100?104.
- ^
[a. Jap. tsunami, tunami, f. tsu harbour + nami waves.?
Oxford English Dictionary
]
- ^
"Definition of Tidal Wave"
. Retrieved
3 November
2016
.
- ^
"Tidal", The American Heritage Stedman's Medical Dictionary.
Houghton Mifflin Company
. 11 November 2008.
Dictionary.reference.com
- ^
-al. (n.d.). Dictionary.com Unabridged (v 1.1). Retrieved November 11, 2008,
Dictionary.reference.com
- ^
"Forty Feet High and It Kills!"
Hawaii Five-O
. Writ. Robert C. Dennis and Edward J. Lakso. Dir. Michael O'Herlihy. CBS, 8 Oct. 1969. Television.
- ^
"Seismic Sea Wave ? Tsunami Glossary"
. Retrieved
3 November
2016
.
- ^
"tsunamis"
. Retrieved
3 November
2016
.
- ^
postcode=3001, corporateName=Bureau of Meteorology; address=GPO Box 1289, Melbourne, Victoria, Australia.
"Joint Australian Tsunami Warning Centre"
. Retrieved
3 November
2016
.
{{
cite web
}}
: CS1 maint: multiple names: authors list (
link
) CS1 maint: numeric names: authors list (
link
)
- ^
Svennevig, Kristian; Hermanns, Reginald L.; Keiding, Marie; Binder, Daniel; Citterio, Michelle; Dahl-Jensen, Trine; Mertl, Stefan; Sørensen, Erik Vest; Voss, Peter H. (23 July 2022).
"A large frozen debris avalanche entraining warming permafrost ground?the June 2021 Assapaat landslide, West Greenland"
.
Landslides
.
19
(11). Springer Link: 2549?2567.
Bibcode
:
2022Lands..19.2549S
.
doi
:
10.1007/s10346-022-01922-7
.
- ^
"International Team Studies Tsunami Deposits in Japan to Improve Understanding and Mitigation of Tsunami Hazards | U.S. Geological Survey"
.
www.usgs.gov
. Retrieved
2024-01-31
.
- ^
Indian Ocean tsunami anniversary: Memorial events held
26 December 2014, BBC News
- ^
The 10 most destructive tsunamis in history
Archived
2013-12-04 at the
Wayback Machine
, Australian Geographic, March 16, 2011.
- ^
Thucydides
:
“A History of the Peloponnesian War”, 3.89.5
- ^
Kelly, Gavin (2004).
"Ammianus and the Great Tsunami"
.
The Journal of Roman Studies
.
94
(141): 141?167.
doi
:
10.2307/4135013
.
hdl
:
20.500.11820/635a4807-14c9-4044-9caa-8f8e3005cb24
.
JSTOR
4135013
.
S2CID
160152988
.
- ^
Stanley, Jean-Daniel & Jorstad, Thomas F. (2005), "
The 365 A.D. Tsunami Destruction of Alexandria, Egypt: Erosion, Deformation of Strata and Introduction of Allochthonous Material
Archived
2017-05-25 at the
Wayback Machine
"
- ^
Haugen, K; Lovholt, F; Harbitz, C (2005). "Fundamental mechanisms for tsunami generation by submarine mass flows in idealised geometries".
Marine and Petroleum Geology
.
22
(1?2): 209?217.
Bibcode
:
2005MarPG..22..209H
.
doi
:
10.1016/j.marpetgeo.2004.10.016
.
- ^
"Tsunami Locations & Occurrences"
. National Weather Service
. Retrieved
16 January
2022
.
- ^
Krieger, Lisa M. (15 January 2022).
"Volcanic tsunamis: Why they are so difficult to predict"
.
The Mercury News
. Retrieved
16 January
2022
.
- ^
"Tsunamis"
.
National Geographic
. Archived from
the original
on April 12, 2021
. Retrieved
16 January
2022
.
- ^
Margaritondo, G (2005).
"Explaining the physics of tsunamis to undergraduate and non-physics students"
(PDF)
.
European Journal of Physics
.
26
(3): 401?407.
Bibcode
:
2005EJPh...26..401M
.
doi
:
10.1088/0143-0807/26/3/007
.
S2CID
7512603
. Archived from
the original
(PDF)
on 2019-02-19.
- ^
Voit, S.S (1987). "Tsunamis".
Annual Review of Fluid Mechanics
.
19
(1): 217?236.
Bibcode
:
1987AnRFM..19..217V
.
doi
:
10.1146/annurev.fl.19.010187.001245
.
- ^
Tia Ghose (2014).
"Are Ocean Asteroid Impacts Really a Serious Threat?"
.
- ^
"How do earthquakes generate tsunamis?"
. University of Washington. Archived from
the original
on 2007-02-03.
- ^
Lynnes, C. S.; Lay, T. (1988),
"Source Process of the Great 1977 Sumba Earthquake"
(PDF)
,
Geophysical Research Letters
,
93
(B11),
American Geophysical Union
: 13, 407?13, 420,
Bibcode
:
1988JGR....9313407L
,
doi
:
10.1029/JB093iB11p13407
- ^
Kanamori H.
(1971). "Seismological evidence for a lithospheric normal faulting ? the Sanriku earthquake of 1933".
Physics of the Earth and Planetary Interiors
.
4
(4): 298?300.
Bibcode
:
1971PEPI....4..289K
.
doi
:
10.1016/0031-9201(71)90013-6
.
- ^
Facts and figures: how tsunamis form
Archived
2013-11-05 at the
Wayback Machine
, Australian Geographic, March 18, 2011.
- ^
George Pararas-Carayannis (1999).
"The Mega-Tsunami of July 9, 1958 in Lituya Bay, Alaska"
. Retrieved
2014-02-27
.
- ^
"alaskashipwreck.com Alaska Shipwrecks (B)"
.
- ^
"alaskashipwreck.com Alaska Shipwrecks (S)"
.
- ^
"Dickson, Ian, "60 Years Ago: The 1958 Earthquake and Lituya Bay Megatsunami," University of Alaska Fairbanks Alaska Earthquake Center, July 13, 2018 Retrieved December 2, 2018"
.
- ^
Petley, Dave (Professor) (2008-12-11).
"The Vaiont (Vajont) landslide of 1963"
. The Landslide Blog. Archived from
the original
on 2013-12-06
. Retrieved
2014-02-26
.
- ^
Duff, Mark (2013-10-10).
"Italy Vajont anniversary: Night of the 'tsunami'
"
.
BBC News
. Bbc.co.uk
. Retrieved
2014-02-27
.
- ^
Pararas-Carayannis, George (2002).
"Evaluation of the threat of mega tsunami generation from postulated massive slope failures of the island volcanoes on La Palma, Canary Islands, and on the island of Hawaii"
.
Science of Tsunami Hazards
.
20
(5): 251?277
. Retrieved
7 September
2014
.
- ^
Paris, R. (2015).
"Source mechanisms of volcanic tsunamis"
.
Phil. Trans. R. Soc
.
373
(2053).
Bibcode
:
2015RSPTA.37340380P
.
doi
:
10.1098/rsta.2014.0380
.
PMID
26392617
.
S2CID
43187708
.
- ^
a
b
Latter, J. H. (1981).
"Tsunamis of volcanic origin: Summary of causes, with particular reference to Krakatoa, 1883"
.
Bulletin Volcanologique
.
44
(3): 467?490.
Bibcode
:
1981BVol...44..467L
.
doi
:
10.1007/BF02600578
.
S2CID
129637214
.
- ^
Day, Simon J. (2015).
"Volcanic Tsunamis"
.
The Encyclopedia of Volcanoes
.
Elsevier
. pp. 993?1009.
doi
:
10.1016/B978-0-12-385938-9.00058-4
.
ISBN
9780123859389
. Retrieved
2022-03-21
.
- ^
Hayward, Matthew. W.; Whittaker, C. N.; Lane, E. M.; Power, W. L.; Popinet, S.; White, J.D.L. (2022).
"Multilayer modelling of waves generated by explosive subaqueous volcanism"
.
Natural Hazards and Earth System Sciences
.
22
(2): 617?637.
Bibcode
:
2022NHESS..22..617H
.
doi
:
10.5194/nhess-22-617-2022
.
- ^
Battershill, L. (2021).
"Numerical Simulations of a Fluidized Granular Flow Entry Into Water: Insights Into Modeling Tsunami Generation by Pyroclastic Density Currents"
.
Journal of Geophysical Research: Solid Earth
.
126
(11).
Bibcode
:
2021JGRB..12622855B
.
doi
:
10.1029/2021JB022855
.
S2CID
243837214
. Archived from
the original
on June 3, 2023.
- ^
a
b
Monserrat, S.; Vilibic, I.; Rabinovich, A. B. (2006).
"Meteotsunamis: atmospherically induced destructive ocean waves in the tsunami frequency band"
.
Natural Hazards and Earth System Sciences
.
6
(6): 1035?1051.
Bibcode
:
2006NHESS...6.1035M
.
doi
:
10.5194/nhess-6-1035-2006
.
- ^
"The Hauraki Gulf Marine Park, Part 2".
Inset to
The New Zealand Herald
. 3 March 2010. p. 9.
- ^
Glasstone, Samuel; Dolan, Philip (1977).
Shock effects of surface and subsurface bursts ? The effects of nuclear weapons
(third ed.). Washington, DC: U.S. Department of Defense; Energy Research and Development Administration.
- ^
Earthsci.org
, Tsunamis
- ^
a
b
"Life of a Tsunami"
.
Western Coastal & Marine Geology
. United States Geographical Survey. 22 October 2008
. Retrieved
2009-09-09
.
- ^
Prof. Stephen A. Nelson (28 January 2009).
"Tsunami"
. Tulane University
. Retrieved
2009-09-09
.
- ^
"Tsunamis in the United States"
.
WorldData
.
- ^
"Tsunamis in Mexico"
.
WorldData
.
- ^
"Tsunamis in Japan"
.
Worlddata.info
.
- ^
"Tsunamis in Taiwan"
.
Worlddata.info
.
- ^
a
b
Gusiakov V.
"Tsunami Quantification: how we measure the overall size of tsunami (Review of tsunami intensity and magnitude scales)"
(PDF)
. Retrieved
2009-10-18
.
- ^
Soloviev, S., & Go, N., 1974 (English transl. 1984),
“Catalogue of tsunamis on the western shore of the Pacific Ocean”
, Canadian Translation of Fisheries and Aquatic Sciences, No. 5077, (310 p).
- ^
Center, National Geophysical Data.
"NGDC/WDS Global Historical Tsunami Database ? NCEI"
. Retrieved
3 November
2016
.
- ^
Lekkas E.; Andreadakis E.; Kostaki I. & Kapourani E. (2013). "A Proposal for a New Integrated Tsunami Intensity Scale (ITIS-2012)".
Bulletin of the Seismological Society of America
.
103
(2B): 1493?1502.
Bibcode
:
2013BuSSA.103.1493L
.
doi
:
10.1785/0120120099
.
- ^
Katsetsiadou, K.N., Andreadakis, E. and Lekkas, E., 2016.
Tsunami intensity mapping: applying the integrated Tsunami Intensity Scale (ITIS2012) on Ishinomaki Bay Coast after the mega-tsunami of Tohoku, March 11, 2011
.
Research in Geophysics
,
5
(1).
- ^
Abe K. (1995).
Estimate of Tsunami Run-up Heights from Earthquake Magnitudes
. Springer.
ISBN
978-0-7923-3483-5
. Retrieved
2009-10-18
.
- ^
"Tsunami Glossary"
.
- ^
"Tsunami Terms"
.
- ^
"津波について"
.
- ^
"津波の高さの定義"
. Retrieved
2012-02-19
.
[
dead link
]
- ^
"Tsunami Amplitude"
.
- ^
Chanson, H.
(2010).
"Tsunami Warning Signs on the Enshu Coast of Japan"
.
Shore & Beach
.
78
(1): 52?54.
ISSN
0037-4237
.
- ^
Lambourne, Helen (2005-03-27).
"Tsunami: Anatomy of a disaster"
. BBC.
- ^
Kenneally, Christine (2004-12-30).
"Surviving the Tsunami: What Sri Lanka's animals knew that humans didn't"
.
Slate Magazine
.
- ^
"Journalist's Resource: Research for Reporting, from Harvard Shorenstein Center"
. Content.hks.harvard.edu. 2012-05-30
. Retrieved
2012-06-12
.
- ^
Phillip Lipscy, Kenji Kushida, and Trevor Incerti. 2013. "
The Fukushima Disaster and Japan’s Nuclear Plant Vulnerability in Comparative Perspective
Archived
2013-10-29 at the
Wayback Machine
".
Environmental Science and Technology
47 (May), 6082?6088.
- ^
Fukada, Takahiro (21 September 2011).
"Iwate fisheries continue struggle to recover"
.
The Japan Times
. p. 3
. Retrieved
2016-09-18
.
- ^
George Pararas-Carayannis.
"The Earthquake and Tsunami of July 12, 1993 in the Sea of Japan/East Sea"
.
www.drgeorgepc.com
. Retrieved
2016-09-18
.
References
- IOC Tsunami Glossary
by the
Intergovernmental Oceanographic Commission
(IOC) at the
International Tsunami Information Centre
(ITIC) of
UNESCO
- Tsunami Terminology
at
NOAA
- In June 2011, the VOA
Special English
service of the
Voice of America
broadcast a 15-minute programme on tsunamis as part of its weekly Science in the News series. The programme included an interview with an NOAA official who oversees the agency's tsunami warning system. A transcript and MP3 of the programme, intended for English learners, can be found at
The Ever-Present Threat of Tsunamis.
- abelard.org.
tsunamis: tsunamis travel fast but not at infinite speed
. retrieved March 29, 2005.
- Dudley, Walter C. & Lee, Min (1988: 1st edition)
Tsunami!
ISBN
0-8248-1125-9
website
- Iwan, W.D.,
editor
, 2006, Summary report of the Great Sumatra Earthquakes and Indian Ocean tsunamis of December 26, 2004 and March 28, 2005: Earthquake Engineering Research Institute, EERI Publication #2006-06, 11 chapters, 100-page summary, plus CD-ROM with complete text and supplementary photographs, EERI Report 2006?06.
ISBN
1-932884-19-X
website
- Kenneally, Christine (December 30, 2004). "Surviving the Tsunami."
Slate
.
website
- Lambourne, Helen (March 27, 2005). "Tsunami: Anatomy of a disaster."
BBC News
.
website
- Macey, Richard (January 1, 2005). "The Big Bang that Triggered A Tragedy,"
The Sydney Morning Herald
, p 11?quoting Dr Mark Leonard, seismologist at Geoscience Australia.
- Interactive Map of Historical Tsunamis
from NOAA National Centers for Environmental Information
- Tappin, D; 2001. Local tsunamis. Geoscientist. 11?8, 4?7.
- Girl, 10, used geography lesson to save lives
,
Telegraph.co.uk
- Philippines warned to prepare for Japan's tsunami
,
Noypi.ph
Further reading
- Boris Levin, Mikhail Nosov:
Physics of tsunamis
. Springer, Dordrecht 2009,
ISBN
978-1-4020-8855-1
.
- Kontar, Y. A. et al.:
Tsunami Events and Lessons Learned: Environmental and Societal Significance.
Springer, 2014.
ISBN
978-94-007-7268-7
(print);
ISBN
978-94-007-7269-4
(eBook).
- Kristy F. Tiampo:
Earthquakes: simulations, sources and tsunamis
. Birkhauser, Basel 2008,
ISBN
978-3-7643-8756-3
.
- Linda Maria Koldau
: Tsunamis. Entstehung, Geschichte, Pravention, (Tsunami development, history and prevention) C.H. Beck, Munich 2013 (C.H. Beck Reihe Wissen 2770),
ISBN
978-3-406-64656-0
(in German).
- Walter C. Dudley, Min Lee:
Tsunami!
University of Hawaii Press, 1988, 1998, Tsunami! University of Hawai'i Press 1999,
ISBN
0-8248-1125-9
,
ISBN
978-0-8248-1969-9
.
- Charles L. Mader
:
Numerical Modeling of Water Waves
CRC Press, 2004,
ISBN
0-8493-2311-8
.
- Harvey Segur, Anjan Kundu,
Tsunami and Nonlinear Waves,
Springer-Verlag Berlin Heidelberg, 2007
ISBN
978-3-540-71255-8
External links
Look up
tsunami
in Wiktionary, the free dictionary.
Wikimedia Commons has media related to
Tsunamis
.
- Reporting Centers
- History & Research
- News & animations
|
---|
Geological
| |
---|
Hydrological
| |
---|
Meteorological
| Temperature
| |
---|
Drought
| |
---|
Cyclonic storms
| |
---|
Other
| |
---|
|
---|
Astronomical
| |
---|