Seiche
Encyclopedia
A seiche is a standing wave
in an enclosed or partially enclosed body of water. Seiches and seiche-related phenomena have been observed on lakes, reservoirs, swimming pools, bays, harbors and seas. The key requirement for formation of a seiche is that the body of water be at least partially bounded, allowing the formation of the standing wave.
The term was promoted by the Swiss hydrologist
François-Alphonse Forel
in 1890, who was the first to make scientific observations of the effect in Lake Geneva
, Switzerland
. The word originates in a Swiss French
dialect word that means "to sway back and forth", which had apparently long been used in the region to describe oscillations in alpine lakes.
Seiches are often imperceptible to the naked eye, and observers in boats on the surface may not notice that a seiche is occurring due to the extremely long wavelengths. The effect is caused by resonances in a body of water that has been disturbed by one or more of a number of factors, most often meteorological effects (wind and atmospheric pressure variations), seismic activity or by tsunami
s. Gravity always seeks to restore the horizontal surface of a body of liquid water, as this represents the configuration in which the water is in hydrostatic equilibrium
. Vertical harmonic motion results, producing an impulse that travels the length of the basin at a velocity that depends on the depth of the water. The impulse is reflected back from the end of the basin, generating interference. Repeated reflections produce standing waves with one or more nodes, or points, that experience no vertical motion. The frequency of the oscillation is determined by the size of the basin, its depth and contours, and the water temperature.
The longest natural period for a seiche in an enclosed rectangular body of water is usually represented by the Merian formula:
where L is the length, h the average depth of the body of water, and g the acceleration of gravity.
Higher order harmonics are also observed. The period of the second harmonic will be half the natural period, the period of the third harmonic will be a third of the natural period, and so forth.
n Great Lakes, seiche is often called slosh. It is always present, but is usually unnoticeable, except during periods of unusual calm. Harbours, bays
, and estuaries are often prone to small seiches with amplitudes of a few centimeters and periods of a few minutes. Seiches can also form in semi-enclosed seas; the North Sea
often experiences a lengthwise seiche with a period of about 36 hours.
The National Weather Service
issues low water advisories for portions of the Great Lakes when seiches of 2 feet or greater are likely to occur. Lake Erie
is particularly prone to wind-caused seiches because of its shallowness and elongation. These can lead to extreme seiches of up to 5 m (16 feet) between the ends of the lake. The effect is similar to a storm surge
like that caused by hurricanes along ocean coasts, but the seiche effect can cause oscillation back and forth across the lake for some time. In 1954, Hurricane Hazel
piled up water along the northwestern Lake Ontario
shoreline near Toronto, causing extensive flooding, and established a seiche that subsequently caused flooding along the south shore.
Lake seiches can occur very quickly: on July 13, 1995, a big seiche on Lake Superior
caused the water level to fall and then rise again by three feet (one meter) within fifteen minutes, leaving some boats hanging from the docks on their mooring lines when the water retreated. The same storm system that caused the 1995 seiche on Lake Superior produced a similar effect in Lake Huron
, in which the water level at Port Huron
changed by six feet (1.8 m) over two hours. On Lake Michigan
, eight fishermen were swept away and drowned when a 10-foot seiche hit the Chicago
waterfront on June 26, 1954.
Lakes in seismically active areas, such as Lake Tahoe
in California
/Nevada
, are significantly at risk from seiches. Geological evidence indicates that the shores of Lake Tahoe may have been hit by seiches and tsunamis as much as 10 m (33 feet) high in prehistoric times, and local researchers have called for the risk to be factored into emergency plans for the region.
Earthquake
-generated seiches can be observed thousands of miles away from the epicentre of a quake. Swimming pools are especially prone to seiches caused by earthquakes, as the ground tremors often match the resonant frequencies of small bodies of water. The 1994 Northridge earthquake
in California
caused swimming pools to overflow across southern California. The massive Good Friday Earthquake
that hit Alaska
in 1964 caused seiches in swimming pools as far away as Puerto Rico
. The earthquake that hit Lisbon, Portugal
in 1755 caused seiches 2,000 miles (3,000 km) away in Loch Lomond, Loch Long, Loch Katrine and Loch Ness in Scotland
http://earthquake.usgs.gov/learning/topics/seiche.php and in canal
s in Sweden
. The 2004 Indian Ocean earthquake
caused seiches in standing water bodies in many Indian states as well as in Bangladesh
, Nepal
and northern Thailand
. Seiches were again observed in Uttar Pradesh
, Tamil Nadu
and West Bengal
in India
as well as in many locations in Bangladesh
during the 2005 Kashmir earthquake
. The 1950 Chayu-Upper Assam earthquake is known to have generated seiches as far as Norway
and southern England
. Other earthquakes in the Indian sub-continent known to have generated seiches include the 1803 Kumaon-Barahat, 1819 Allah Bund, 1842 Central Bengal, 1905 Kangra, 1930 Dhubri, 1934 Nepal-Bihar, 2001 Bhuj, 2005 Nias, 2005 Teresa Island earthquakes. The February 27, 2010 Chile earthquake
produced a seiche on Lake Pontchartrain
, Louisiana
with a height of around 0.5 feet. Seiches up to at least 1.8 m (6 feet) were observed in Sognefjorden, Norway
during the 2011 Tōhoku earthquake.
and the Baltic Sea
, resulting in flooding of Venice
and St. Petersburg respectively. The latter is constructed on drained marshlands at the mouth of the Neva river. Seiche-induced flooding is common along the Neva river in the autumn. The seiche is driven by a low pressure region in the North Atlantic moving onshore, giving rise to cyclonic
lows on the Baltic Sea
. The low pressure of the cyclone draws greater-than-normal quantities of water into the virtually land-locked Baltic. As the cyclone continues inland, long, low-frequency seiche waves with wavelengths up to several hundred kilometers are established in the Baltic. When the waves reach the narrow and shallow Neva Bay, they become much higher — ultimately flooding the Neva embankments. Similar phenomena are observed at Venice, resulting in the MOSE Project
, a system of 79 mobile barriers designed to protect the three entrances to the Venetian Lagoon
.
Nagasaki Bay
is a typical area in Japan where seiches have been observed from time to time, most often in the spring — especially in March. On 31 March 1979, the Nagasaki
tide station recorded a maximum water-level displacement of 2.78 metres (9.1 ft), at that location and due to the seiche. The maximum water-level displacement in the whole bay during this seiche event is assumed to have reached 4.7 metres (15.4 ft), at the bottom of the bay. Seiches in Western Kyushu
— including Nagasaki Bay — are often induced by a low in the atmospheric pressure passing South of Kyushu island. Seiches in Nagasaki Bay have a period of about 30 to 40 minutes. Locally, seiche is called Abiki. The word of Abiki is considered to have been derived from Amibiki, which literally means: the dragging-away (biki) of a fishing net (ami). Seiches not only cause damage to the local fishery but also may result in flooding of the coast around the bay, as well as in the destruction of port
facilities.
Seiches can also be induced by tsunami
, a wave train (series of waves) generated in a body of water by a pulsating or abrupt disturbance that vertically displaces the water column. On occasion, tsunamis can produce seiches as a result of local geographic peculiarities. For instance, the tsunami that hit Hawaii
in 1946 had a fifteen-minute interval between wave fronts. The natural resonant period of Hilo Bay is about thirty minutes. That meant that every second wave was in phase with the motion of Hilo Bay, creating a seiche in the bay. As a result, Hilo suffered worse damage than any other place in Hawaii, with the tsunami/seiche reaching a height of 26 feet along the Hilo Bayfront, killing 96 people in the city alone. Seiche waves may continue for several days after a tsunami.
in constrained bodies of water.
), reservoirs and dams (e.g., Grand Coulee Dam
), potable water storage basins, harbours and even spent nuclear fuel storage basins.
Relationship to aquatic "monsters"
Standing wave
In physics, a standing wave – also known as a stationary wave – is a wave that remains in a constant position.This phenomenon can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling...
in an enclosed or partially enclosed body of water. Seiches and seiche-related phenomena have been observed on lakes, reservoirs, swimming pools, bays, harbors and seas. The key requirement for formation of a seiche is that the body of water be at least partially bounded, allowing the formation of the standing wave.
The term was promoted by the Swiss hydrologist
Hydrology
Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
François-Alphonse Forel
François-Alphonse Forel
François-Alphonse Forel was a Swiss scientist who pioneered the study of lakes, and is thus considered the founder of limnology....
in 1890, who was the first to make scientific observations of the effect in Lake Geneva
Lake Geneva
Lake Geneva or Lake Léman is a lake in Switzerland and France. It is one of the largest lakes in Western Europe. 59.53 % of it comes under the jurisdiction of Switzerland , and 40.47 % under France...
, Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
. The word originates in a Swiss French
Swiss French
Swiss French is the name used for the variety of French spoken in the French-speaking area of Switzerland known as Romandy. Swiss French is not to be confused with Franco-Provençal/Arpitan or Romansh, two other individual Romance languages spoken in areas not far from Romandy.The differences...
dialect word that means "to sway back and forth", which had apparently long been used in the region to describe oscillations in alpine lakes.
Causes and nature of seiches
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
s. Gravity always seeks to restore the horizontal surface of a body of liquid water, as this represents the configuration in which the water is in hydrostatic equilibrium
Hydrostatic equilibrium
Hydrostatic equilibrium or hydrostatic balance is the condition in fluid mechanics where a volume of a fluid is at rest or at constant velocity. This occurs when compression due to gravity is balanced by a pressure gradient force...
. Vertical harmonic motion results, producing an impulse that travels the length of the basin at a velocity that depends on the depth of the water. The impulse is reflected back from the end of the basin, generating interference. Repeated reflections produce standing waves with one or more nodes, or points, that experience no vertical motion. The frequency of the oscillation is determined by the size of the basin, its depth and contours, and the water temperature.
The longest natural period for a seiche in an enclosed rectangular body of water is usually represented by the Merian formula:
where L is the length, h the average depth of the body of water, and g the acceleration of gravity.
Higher order harmonics are also observed. The period of the second harmonic will be half the natural period, the period of the third harmonic will be a third of the natural period, and so forth.
Seiches around the world
Seiches have been observed on both lakes and seas. The key requirement is that the body of water be partially constrained to allow formation of standing waves. Regularity of geometry is not required, even harbors with exceedingly irregular shapes are routinely observed to oscillate with very stable frequencies.Lake seiches
Small rhythmic seiches are almost always present on larger lakes. On the North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n Great Lakes, seiche is often called slosh. It is always present, but is usually unnoticeable, except during periods of unusual calm. Harbours, bays
Headlands and bays
Headlands and bays are two related features of the coastal environment.- Geology and geography :Headlands and bays are often found on the same coastline. A bay is surrounded by land on three sides, whereas a headland is surrounded by water on three sides. Headlands are characterized by high,...
, and estuaries are often prone to small seiches with amplitudes of a few centimeters and periods of a few minutes. Seiches can also form in semi-enclosed seas; the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
often experiences a lengthwise seiche with a period of about 36 hours.
National Weather Service
The National Weather Service , once known as the Weather Bureau, is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration of the United States government...
issues low water advisories for portions of the Great Lakes when seiches of 2 feet or greater are likely to occur. Lake Erie
Lake Erie
Lake Erie is the fourth largest lake of the five Great Lakes in North America, and the tenth largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also has the shortest average water residence time. It is bounded on the north by the...
is particularly prone to wind-caused seiches because of its shallowness and elongation. These can lead to extreme seiches of up to 5 m (16 feet) between the ends of the lake. The effect is similar to a storm surge
Storm surge
A storm surge is an offshore rise of water associated with a low pressure weather system, typically tropical cyclones and strong extratropical cyclones. Storm surges are caused primarily by high winds pushing on the ocean's surface. The wind causes the water to pile up higher than the ordinary sea...
like that caused by hurricanes along ocean coasts, but the seiche effect can cause oscillation back and forth across the lake for some time. In 1954, Hurricane Hazel
Hurricane Hazel
Hurricane Hazel was the deadliest and costliest hurricane of the 1954 Atlantic hurricane season. The storm killed as many as 1,000 people in Haiti before striking the United States near the border between North and South Carolina, as a Category 4 hurricane...
piled up water along the northwestern Lake Ontario
Lake Ontario
Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north and southwest by the Canadian province of Ontario, and on the south by the American state of New York. Ontario, Canada's most populous province, was named for the lake. In the Wyandot language, ontarío means...
shoreline near Toronto, causing extensive flooding, and established a seiche that subsequently caused flooding along the south shore.
Lake seiches can occur very quickly: on July 13, 1995, a big seiche on Lake Superior
Lake Superior
Lake Superior is the largest of the five traditionally-demarcated Great Lakes of North America. It is bounded to the north by the Canadian province of Ontario and the U.S. state of Minnesota, and to the south by the U.S. states of Wisconsin and Michigan. It is the largest freshwater lake in the...
caused the water level to fall and then rise again by three feet (one meter) within fifteen minutes, leaving some boats hanging from the docks on their mooring lines when the water retreated. The same storm system that caused the 1995 seiche on Lake Superior produced a similar effect in Lake Huron
Lake Huron
Lake Huron is one of the five Great Lakes of North America. Hydrologically, it comprises the larger portion of Lake Michigan-Huron. It is bounded on the east by the Canadian province of Ontario and on the west by the state of Michigan in the United States...
, in which the water level at Port Huron
Port Huron
Port Huron is the name of a city and a township in St. Clair County, Michigan. See:* Port Huron, Michigan* Port Huron Township, MichiganSee also:* Port Huron Statement...
changed by six feet (1.8 m) over two hours. On Lake Michigan
Lake Michigan
Lake Michigan is one of the five Great Lakes of North America and the only one located entirely within the United States. It is the second largest of the Great Lakes by volume and the third largest by surface area, after Lake Superior and Lake Huron...
, eight fishermen were swept away and drowned when a 10-foot seiche hit the Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
waterfront on June 26, 1954.
Lakes in seismically active areas, such as Lake Tahoe
Lake Tahoe
Lake Tahoe is a large freshwater lake in the Sierra Nevada of the United States. At a surface elevation of , it is located along the border between California and Nevada, west of Carson City. Lake Tahoe is the largest alpine lake in North America. Its depth is , making it the USA's second-deepest...
in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
/Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
, are significantly at risk from seiches. Geological evidence indicates that the shores of Lake Tahoe may have been hit by seiches and tsunamis as much as 10 m (33 feet) high in prehistoric times, and local researchers have called for the risk to be factored into emergency plans for the region.
Earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
-generated seiches can be observed thousands of miles away from the epicentre of a quake. Swimming pools are especially prone to seiches caused by earthquakes, as the ground tremors often match the resonant frequencies of small bodies of water. The 1994 Northridge earthquake
Northridge earthquake
The Northridge earthquake was a massive earthquake that occurred on January 17, 1994, at 04:31 Pacific Standard Time in Reseda, a neighborhood in the city of Los Angeles, California, lasting for about 10–20 seconds...
in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
caused swimming pools to overflow across southern California. The massive Good Friday Earthquake
Good Friday Earthquake
The 1964 Alaska earthquake, also known as the Great Alaskan Earthquake, the Portage Earthquake and the Good Friday Earthquake, was a megathrust earthquake that began at 5:36 P.M. AST on Good Friday, March 27, 1964...
that hit Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
in 1964 caused seiches in swimming pools as far away as Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
. The earthquake that hit Lisbon, Portugal
1755 Lisbon earthquake
The 1755 Lisbon earthquake, also known as the Great Lisbon Earthquake, was a megathrust earthquake that took place on Saturday 1 November 1755, at around 9:40 in the morning. The earthquake was followed by fires and a tsunami, which almost totally destroyed Lisbon in the Kingdom of Portugal, and...
in 1755 caused seiches 2,000 miles (3,000 km) away in Loch Lomond, Loch Long, Loch Katrine and Loch Ness in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
http://earthquake.usgs.gov/learning/topics/seiche.php and in canal
Canal
Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...
s in Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. The 2004 Indian Ocean earthquake
2004 Indian Ocean earthquake
The 2004 Indian Ocean earthquake was an undersea megathrust earthquake that occurred at 00:58:53 UTC on Sunday, December 26, 2004, with an epicentre off the west coast of Sumatra, Indonesia. The quake itself is known by the scientific community as the Sumatra-Andaman earthquake...
caused seiches in standing water bodies in many Indian states as well as in Bangladesh
Bangladesh
Bangladesh , officially the People's Republic of Bangladesh is a sovereign state located in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south...
, Nepal
Nepal
Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...
and northern Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
. Seiches were again observed in Uttar Pradesh
Uttar Pradesh
Uttar Pradesh abbreviation U.P. , is a state located in the northern part of India. With a population of over 200 million people, it is India's most populous state, as well as the world's most populous sub-national entity...
, Tamil Nadu
Tamil Nadu
Tamil Nadu is one of the 28 states of India. Its capital and largest city is Chennai. Tamil Nadu lies in the southernmost part of the Indian Peninsula and is bordered by the union territory of Pondicherry, and the states of Kerala, Karnataka, and Andhra Pradesh...
and West Bengal
West Bengal
West Bengal is a state in the eastern region of India and is the nation's fourth-most populous. It is also the seventh-most populous sub-national entity in the world, with over 91 million inhabitants. A major agricultural producer, West Bengal is the sixth-largest contributor to India's GDP...
in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
as well as in many locations in Bangladesh
Bangladesh
Bangladesh , officially the People's Republic of Bangladesh is a sovereign state located in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south...
during the 2005 Kashmir earthquake
2005 Kashmir earthquake
The 2005 Kashmir earthquake was a major earthquake centered in Pakistan-administered Kashmir known as Azad Kashmir, near the city of Muzaffarabad, affecting Gilgit-Baltistan and Khyber Pakhtunkhwa province of Pakistan. It occurred at 08:52:37 Pakistan Standard Time on 8 October 2005...
. The 1950 Chayu-Upper Assam earthquake is known to have generated seiches as far as Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
and southern England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. Other earthquakes in the Indian sub-continent known to have generated seiches include the 1803 Kumaon-Barahat, 1819 Allah Bund, 1842 Central Bengal, 1905 Kangra, 1930 Dhubri, 1934 Nepal-Bihar, 2001 Bhuj, 2005 Nias, 2005 Teresa Island earthquakes. The February 27, 2010 Chile earthquake
2010 Chile earthquake
The 2010 Chile earthquake occurred off the coast of central Chile on Saturday, 27 February 2010, at 03:34 local time , having a magnitude of 8.8 on the moment magnitude scale, with intense shaking lasting for about three minutes. It ranks as the sixth largest earthquake ever to be recorded by a...
produced a seiche on Lake Pontchartrain
Lake Pontchartrain
Lake Pontchartrain is a brackish estuary located in southeastern Louisiana. It is the second-largest inland saltwater body of water in the United States, after the Great Salt Lake in Utah, and the largest lake in Louisiana. As an estuary, Pontchartrain is not a true lake.It covers an area of with...
, Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
with a height of around 0.5 feet. Seiches up to at least 1.8 m (6 feet) were observed in Sognefjorden, Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
during the 2011 Tōhoku earthquake.
Sea and bay seiches
Seiches have been observed in seas such as the Adriatic SeaAdriatic Sea
The Adriatic Sea is a body of water separating the Italian Peninsula from the Balkan peninsula, and the system of the Apennine Mountains from that of the Dinaric Alps and adjacent ranges...
and the Baltic Sea
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
, resulting in flooding of Venice
Venice
Venice is a city in northern Italy which is renowned for the beauty of its setting, its architecture and its artworks. It is the capital of the Veneto region...
and St. Petersburg respectively. The latter is constructed on drained marshlands at the mouth of the Neva river. Seiche-induced flooding is common along the Neva river in the autumn. The seiche is driven by a low pressure region in the North Atlantic moving onshore, giving rise to cyclonic
Cyclone
In meteorology, a cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth. This is usually characterized by inward spiraling winds that rotate anticlockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth. Most large-scale...
lows on the Baltic Sea
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...
. The low pressure of the cyclone draws greater-than-normal quantities of water into the virtually land-locked Baltic. As the cyclone continues inland, long, low-frequency seiche waves with wavelengths up to several hundred kilometers are established in the Baltic. When the waves reach the narrow and shallow Neva Bay, they become much higher — ultimately flooding the Neva embankments. Similar phenomena are observed at Venice, resulting in the MOSE Project
MOSE Project
The MOSE Project is a project intended to protect the city of Venice, Italy from floods...
, a system of 79 mobile barriers designed to protect the three entrances to the Venetian Lagoon
Venetian Lagoon
The Venetian Lagoon is the enclosed bay of the Adriatic Sea in which the city of Venice is situated. Its name in the Venetian language, Laguna Veneta— cognate of Latin lacus, "lake"— has provided the international name for an enclosed, shallow embayment of saltwater, a lagoon.The Venetian Lagoon...
.
Nagasaki Bay
Ōmura Bay
is a bay of the East China Sea in the centre of the Japanese Nagasaki Prefecture.- Geography :The bay measures about north-to-south and east-to-west. The length of the shoreline is about and the surface area is about . This corresponds with about 8% of the total area of the prefecture...
is a typical area in Japan where seiches have been observed from time to time, most often in the spring — especially in March. On 31 March 1979, the Nagasaki
Nagasaki
is the capital and the largest city of Nagasaki Prefecture on the island of Kyushu in Japan. Nagasaki was founded by the Portuguese in the second half of the 16th century on the site of a small fishing village, formerly part of Nishisonogi District...
tide station recorded a maximum water-level displacement of 2.78 metres (9.1 ft), at that location and due to the seiche. The maximum water-level displacement in the whole bay during this seiche event is assumed to have reached 4.7 metres (15.4 ft), at the bottom of the bay. Seiches in Western Kyushu
Kyushu
is the third largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include , , and . The historical regional name is referred to Kyushu and its surrounding islands....
— including Nagasaki Bay — are often induced by a low in the atmospheric pressure passing South of Kyushu island. Seiches in Nagasaki Bay have a period of about 30 to 40 minutes. Locally, seiche is called Abiki. The word of Abiki is considered to have been derived from Amibiki, which literally means: the dragging-away (biki) of a fishing net (ami). Seiches not only cause damage to the local fishery but also may result in flooding of the coast around the bay, as well as in the destruction of port
Port
A port is a location on a coast or shore containing one or more harbors where ships can dock and transfer people or cargo to or from land....
facilities.
Seiches can also be induced by tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
, a wave train (series of waves) generated in a body of water by a pulsating or abrupt disturbance that vertically displaces the water column. On occasion, tsunamis can produce seiches as a result of local geographic peculiarities. For instance, the tsunami that hit Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
in 1946 had a fifteen-minute interval between wave fronts. The natural resonant period of Hilo Bay is about thirty minutes. That meant that every second wave was in phase with the motion of Hilo Bay, creating a seiche in the bay. As a result, Hilo suffered worse damage than any other place in Hawaii, with the tsunami/seiche reaching a height of 26 feet along the Hilo Bayfront, killing 96 people in the city alone. Seiche waves may continue for several days after a tsunami.
Underwater (internal) waves
Although the bulk of the technical literature addresses surface seiches, which are readily observed, seiches are also observed beneath the lake surface acting along the thermoclineThermocline
A thermocline is a thin but distinct layer in a large body of fluid , in which temperature changes more rapidly with depth than it does in the layers above or below...
in constrained bodies of water.
Engineering for seiche protection
Engineers consider seiche phenomena in the design of flood protection works (e.g., Saint Petersburg DamSaint Petersburg Dam
The Saint Petersburg Flood Prevention Facility Complex , unofficially the Saint Petersburg Dam, is a complex of dams for flood control near Saint Petersburg, Russia...
), reservoirs and dams (e.g., Grand Coulee Dam
Grand Coulee Dam
Grand Coulee Dam is a gravity dam on the Columbia River in the U.S. state of Washington built to produce hydroelectric power and provide irrigation. It was constructed between 1933 and 1942, originally with two power plants. A third power station was completed in 1974 to increase its energy...
), potable water storage basins, harbours and even spent nuclear fuel storage basins.
See also
- ClapotisClapotisIn hydrodynamics, the clapotis is a non-breaking standing wave pattern, caused for example, by the reflection of a traveling surface wave train from a near vertical shoreline like a breakwater, seawall or steep cliff....
- Earthquake engineeringEarthquake engineeringEarthquake engineering is the scientific field concerned with protecting society, the natural and the man-made environment from earthquakes by limiting the seismic risk to socio-economically acceptable levels...
- Severe weather terminology (United States)Severe weather terminology (United States)This article describes the United States National Weather Service severe weather terminology. The NWS defines precise meanings for nearly all its weather terms. This article describes NWS terminology and related NWS weather scales...
- Severe weather terminology (Canada)Severe weather terminology (Canada)This article describes Severe weather Terminology used by the Environment Canada's Meteorological Service of Canada. This article primarily describes various weather warnings, and their criteria. Related weather scales and general weather terms are also addressed in this article...
- Tsunami hazard in lakes
- Vajont DamVajont DamThe Vajont Dam is a disused dam, completed in 1959 in the valley of the Vajont river under Monte Toc, 100 km north of Venice, Italy...
External links
General- What is a seiche?
- Seiche. Encyclopædia Britannica. Retrieved January 24, 2004, from Encyclopædia Britannica Premium Service.
- Seiche calculator
- Bonanza for Lake Superior: Seiches Do More Than Move Water
- Great Lakes Storms Photo Gallery Seiches, Storm Surges, and Edge Waves from NOAA
Relationship to aquatic "monsters"
- The Unmuseum
- "The Legend of the Lake Champlain Monster" in The Skeptical Inquirer
- Geological page