Sieches

A seiche is a standing wave in an enclosed or partially enclosed body of water. These waves occur when a body of water is disturbed by a sudden change in atmospheric pressure or by earthquakes, strong winds, or even by passing ships. The disturbance causes the water to oscillate back and forth from one end of the basin to the other. The water level rises at one end and falls at the other, then reverses. This movement is similar to the sloshing of water in a bathtub or sink when it is disturbed.

The amplitude of a seiche can vary greatly, from imperceptible movements to several meters. The period of oscillation, which is the time it takes for one complete cycle of the wave, depends on the size and shape of the body of water. Larger and deeper bodies of water tend to have longer periods. Seiches are most commonly observed in lakes, gulfs, bays, and harbors. Famous examples include the seiches on Lake Geneva, known as "lipions," and the seiches in Nagasaki Harbor, which played a role in the destruction caused by the atomic bomb.

While often minor, seiches can have significant impacts. In some cases, they can cause flooding or unusually low water levels in affected areas. They can also pose a hazard to boats and docks. The study of seiches is important for understanding water dynamics in various aquatic environments and for predicting potential impacts on coastal communities and ecosystems. Meteorologists and oceanographers use various instruments to detect and measure seiches.