Seiche
Seiches and seiche-related phenomena have been observed on lakes, reservoirs, swimming pools, bays, harbors, caves, and seas.
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.
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.
Regularity of geometry is not required; even harbours with exceedingly irregular shapes are routinely observed to oscillate with very stable frequencies.
The National Weather Service issues low water advisories for portions of the Great Lakes when seiches of 0.6 metres (2 ft) or greater are likely to occur.
Geological evidence indicates that the shores of Lake Tahoe may have been hit by seiches and tsunamis as much as 10 metres (33 ft) high in prehistoric times, and local researchers have called for the risk to be factored into emergency plans for the region.
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 massive Good Friday earthquake that hit Alaska in 1964 caused seiches in swimming pools as far away as Puerto Rico.
[17] 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 February 27, 2010 Chile earthquake produced a seiche on Lake Pontchartrain, Louisiana, with a height of around 150 millimetres (0.5 ft).
The seiche is driven by a low-pressure region in the North Atlantic moving onshore, giving rise to cyclonic lows on the Baltic Sea.
As the cyclone continues inland, long, low-frequency seiche waves with wavelengths up to several hundred kilometres are established in the Baltic.
[22] 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.
Seiches in Western Kyushu—including Nagasaki Bay—are often induced by a low in the atmospheric pressure passing South of Kyushu island.
As a result, Hilo suffered worse damage than any other place in Hawaii, with the combined tsunami and seiche reaching a height of 26 feet (7.9 m) along the Bayfront, killing 96 people in the city alone.
Tide-generated internal solitary waves (solitons) can excite coastal seiches at the following locations: Magueyes Island in Puerto Rico,[24][25][26] Puerto Princesa in Palawan Island,[27] Trincomalee Bay in Sri Lanka,[28][29] and in the Bay of Fundy in eastern Canada, where seiches cause some of the highest recorded tidal fluctuations in the world.
[31] In September 2023, an enormous landslide resulting from a melting glacier near Dickson Fjord in Greenland triggered a megatsunami about 200 metres (660 ft) high.
[35] This seiche lasted nine days, reflecting the avalanche's large size and the fjord's long, narrow shape.
During that period, it generated unusual seismic reverberations detected around the world, puzzling seismologists for some time before they could identify their source.
As the thermocline moves up and down a sloping lake bed, it creates a 'swash zone', where temperatures can vary rapidly,[39] potentially affecting fish habitat.
[42] When such non-linear waves break on the lake bed, they can be an important source of turbulence and have the potential for sediment resuspension[43] On September 19, 2022, a seiche reaching 4 feet (1.2 metres) occurred at Devils Hole at Death Valley National Park in the U.S. after a 7.6-magnitude earthquake hit western Mexico, about 1,500 miles (2,400 kilometres) away.
