Hydrological Disasters

A hydrological disaster refers to a violent, sudden and destructive change either in the quality of the earth's water or in the distribution or movement of water on land, below the surface or in the atmosphere. Some examples are:
Floods

liiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii






























































































































































































































Eruptions

Tsunami

Floods
— Floods are among the most frequent and costly natural disasters.
— Conditions that cause floods include heavy or steady rain for several hours or days that saturates the ground.
— Flash floods occur suddenly due to rapidly rising water along a stream or low­lying area.

Limnic Eruptions
A limnic eruption, also referred to as a lake overturn, is a rare type of natural disaster in which carbon dioxide (CO2) suddenly erupts from deep lake water, suffocating wildlife, livestock and humans.

— Such an eruption may also cause tsunamis in the lake as the rising CO2 displaces water. Scientists believe landslides, volcanic activity, or explosions can trigger such an eruption. Lakes in which such activity occurs may be known as limnically active lakes or exploding lakes.

Some features of limnically active lakes include:
— CO2-saturated incoming water
— A cool lake bottom indicating an absence of direct volcanic interaction with lake waters
— An upper and lower thermal layer with differing CO2 saturations
— Proximity to areas with volcanic activity

Tsunami
— A tsunami is a series of ocean waves that sends huge surges of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash onto shore.
— Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour—about as fast as a jet airplane. At that pace they can cross the entire expanse of the Pacific Ocean in less than a day. And their long wavelengths mean they lose very little energy along the way.

What causes a Tsunami?
— These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly it displaces the water above it and launches the rolling waves that will become a tsunami.
— Tsunamis may also be caused by underwater landslides or volcanic eruptions.
— They may even be launched, as they frequently were in Earth’s ancient past, by the impact of a large meteorite plunging into an ocean.

Video on how Tsunami’s are created:
http://www.youtube.com/watch?v=L-hMedWQjUg

Images of Hydrological Disasters

Tsunami
external image application.pdf
Floods
external image application.pdf
Limnic Eruptions
external image application.pdf