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Seiche

A seiche (pronounced SAYSH) or an underwater wave is an underwater, irregular fluctuation or rhythmic rocking of the water level of a lake, first noted in Lake Geneva, Switzerland. Observers on the surface may not know a seiche is happening.

Scientifically, a seiche is a standing wave in an enclosed body of water and the definition does not include the causes.

Seiches are common between warm and cold-water layers, notably in Loch Ness, Scotland, and some evidence cited for the Loch Ness monster and the Lake Champlain monster (see also Lake monster and Sea monster) may trace to seiches.

Small rhythmic seiches are almost always present on larger lakes, and the frequency of the oscillation is determined by the size of the body, its depth and contours, and the water temperature. On the North American Great Lakes seiche is often called slosh. It is always present but is usually unnoticeable except during periods of unusual calm.

Major seiches often occur during earthquakes and may be caused by wind or underwater landslides. Lake Erie, because of its shallowness and elongation can occasionally have wind caused extreme seiches of up to 15 feet (5 meters) between the ends. The first appearance is similar to a storm surge like those caused by hurricanes along ocean coasts, but the seiche effect can cause oscillation back and forth across the lake for some time. 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.

A related effect is the 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.

External links and references

General:

  • What is a seiche? http://www.seagrant.wisc.edu/communications/lakelevels/seiche.htm
  • Seiche. Encyclopędia Britannica. Retrieved January 24, 2004, from Encyclopędia Britannica Premium Service. http://www.britannica.com/eb/article?eu=68339
  • Seiche calculator http://www.coastal.udel.edu/faculty/rad/seiche.html
  • Seiche acoustics page http://www.seiche.com/

On aquatic monsters:

  • The unmuseum on seiches & their relationhip to aquatic monsters http://www.unmuseum.org/mwave.htm
  • The Skeptical Inquirer on seiches & their relationhip to aquatic monsters http://www.csicop.org/si/2003-07/i-files.html
  • Geological page on seiches & their relationhip to aquatic monsters http://geology.about.com/library/weekly/aa070101a.htm

The French term:

  • On the French meaning of seiche http://www.fao.org/figis/servlet/org.fao.fi.common.FiRefServlet?ds=species&fid=2
    711



Seiche is also a French term for a type of cuttlefish.

Last updated: 02-08-2005 07:33:36
Last updated: 05-03-2005 17:50:55