Seiche

As a seiche (French / sɛʃ / ) refers to standing waves of the water in lakes, bays or docks.

They arise when Beck edges reflect waves whose wavelength is in resonance with the pelvis. Coined the term by François- Alphonse Forel, who explored the Lake Geneva end of the 19th century and described. The term he led her from the tide -like drying up of bank areas, which he watched repeatedly by the lake. Note the seiches of the Great Lakes of North America, where up to three meters high fluctuations of water level are observed.

In simple terms, let Seiches with the sloshing of the water compare in a giant bowl. But this case also occur prior waves with multiple wave nodes and complex wave systems (longitudinal and transverse superimposed) according to the different length and width of the lake basin or even more complicated due to pool shapes.

The periods of the oscillations are between seconds and days (in the Baltic Sea about a day in the Fjords of Norway three days in swimming pools seconds). Triggers are mostly in lakes varying wind effects. In marine basin earthquakes or tsunamis occur as a trigger in question. ( The extreme impact of the tsunami of 1946 in Hilo / Hawaii are attributed to its amplification by the seiche of the Bay of Hilo: period of the tsunami 15 min period of the seiche 30 minutes, thereby increasing every second wave generated by the proper motion of the Hilobucht and a much greater destruction than the other coastal areas of Hawaii. )

Because of different densities are layered in lakes water masses are regular internal seiches, which were only discovered in the late 19th century ( Müller- Navarra, 2005). The water masses of the various layers move against each other, so that the layers at a time have different thicknesses in different areas of the lake and this distribution changes periodically. Such internal wave systems have been explored in detail for example in Lake Constance and Lake Chiemsee.