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Hydrological disasters

2018-09-20  |   Editor : houguangbing  

This is a violent, sudden and destructive change, whether it is on the quality of the surface of the earth, or on the distribution or movement of water in the surface or atmosphere.


A flood is an overflow of water that 'submerges' land. The EU Flood Directive defines a flood as a temporary covering by water of land which is usually not covered by water.In the sense of 'flowing water', the word may also be applied to the inflow of the tides. Flooding may result from the volume of water within a body of water, such as a river or a lake, which overflows causing the result that some of the water escapes its usual boundaries. While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, it is not a significant flood unless the water covers land used by the man like a village, city or other inhabited area, roads, expanses of farmland, etc.

The Limpopo River during the 2000 Mozambique flood

Limnic eruptions

A limnic eruption occurs when a gas, usually carbon dioxide , suddenly erupts from deep lake water, posing the threat of suffocating wildlife, livestock and humans. Such an eruption may also cause tsunamis in the lake as the rising gas displaces water. Scientists believe that landslides, volcanic activity, or explosions can trigger such an eruption. To date, only two limnic eruptions have been observed and recorded. In 1984, in Cameroon, a limnic eruption in Lake Monoun caused the deaths of 37 nearby residents, and at nearby Lake Nyos in 1986 a much larger eruption killed between 1,700 and 1,800 people by asphyxiation.


A tsunami, also known as a seismic sea wave or a tidal wave, is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Tsunamis can be caused by undersea earthquakes such as the 2004 Boxing Day tsunami, or by landslides such as the one in 1958 at Lituya Bay, Alaska, or by volcanic eruptions such as the ancient eruption of Santorini. On March 11, 2011, a tsunami occurred near Fukushima, Japan and spread through the Pacific.

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