Natural Hazards

Natural Hazards
Natural hazards are defined as , “those elements of the phyical environment, harmful to man and caused by forces extraneous to him.” The prefix “natural” shows that these exclude phenomenon that are a result of human action. An event that cause large numbers of fatalities and tremendous loss of property is a ‘natural disaster.’
Violent volcano
One of the most explosively violent elements on Earth is that of an errupting volcano as it spews forth molten lava. There are few sights more awe-inspiring than the sight of red hot lava glinting through the cracks on the softy black crust as the river of molten matter winds its way through the landscape. The most common conception about a volcano is that it is a mountain with a hole/crater at the top through which a lava escapes. Not everybody realizes that unlike most mountains, which are pushed up from below, volcanoes are built up by an accumulation of the same materials that they eject.
Volcano Architecture
A volcano constitutes a vent, a pipe, a crater and a cone.
Vent-This is the opening through which volcanic materials is ejected. A central vent underlies the summit crater of the volcano. It is connected to a magma chamber, which is the main storage area for material that is finally ejected.
Pipe- This is a passageway through which the ejected magma rises to the surface.
Crater-This is the ionic bowl-shaped depression at the top of the volcano.
Cone- Solidified lava, ashes and cinder form the cone and it rises higher with each erruption. The sides of the volcano often contain fractures that connect to the central vent or to shallow magma chambers. Magma is ejected through the sides of the volcano via these fractures. Such erruptions lead to cone shaped accumulations called parasitic cones. Fractures are also conduits for escaping gases, which are released through openings called fumaroles.
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