Megatsunami

Megatsunamis occur when a large amount of material suddenly falls into water or anywhere near water. They can have extremely high initial wave heights of hundreds and possibly thousands of metres, far beyond any ordinary tsunami. Two heights are sometimes quoted for megatamis – the height of the wave itself, and the height to which it surges when it reaches land, which, depending upon the locale, can be several times larger.

About Megatsunami in brief

Summary MegatsunamiA megatsunami is a very large wave created by a large, sudden displacement of material into a body of water. Most tsunamis are caused by underwater tectonic activity and as a result of earthquake and rise or fall in the sea floor, causing water to be displaced. Megatsunamis occur when a large amount of material suddenly falls into water or anywhere near water. They can have extremely high initial wave heights of hundreds and possibly thousands of metres, far beyond any ordinary tsunami. Two heights are sometimes quoted for megatamis – the height of the wave itself, and the height to which it surges when it reaches land, which, depending upon the locale, can be several times larger. The mechanism giving rise to the megatami in Lituya Bay was analysed for the first time in a study presented at the Tsunami Society in London. The study presented the evidence for the rise to 100 feet in a megatunami in the bay in a report by Howard Ulrich and his son Howard Jr. The report was published in the Journal of Volcanology and Seismology, published by the University of California, Los Angeles. It is available online at: http://www.volcanologyandseismology.org/magazines/magazine/volcano-and-seismic-extremism/megatunams/megatsunams-in-lituya-bay- 1958-lithuya.html.

It also includes: ‘Megatsunamas in Alaska’, ‘Lituyas in Alaska,’ and ‘‘Lithuyan Tsunams’ in the Pacific Ocean’. ‘Megatunam’ is a term used to refer to the one associated with the 1883 eruption of Krakatoa, and the one resulting from the Vajont Dam landslide in 1958. “Megatsuns’ refers to a meteorite hitting an ocean, and could also refer to a landslide or other impact event, such as the Chicxulub, Chesapeake Bay and Eltanin meteor impacts.   ‘ megatsuns ’ refer to an event in which a large volume of water is thrown into the ocean, causing a surge of water to run-off at the sides of the body.    ‘megatssunamis’ can be caused by earthquakes or volcanic eruptions, but landslides next to bodies of water resulting from earthquakes can, since they cause a large. amount of displacement. If the landslide or impact occurs in a limited body of. water, then the water may be unable to disperse and one or more exceedingly large waves may result.’   The study was presented in a journal of the Volcanologists and Seamountists in California, and was published online by the Volcanology & Seismologists Society in Los Angeles, California, on July 9, 2008.