natural disasters

definition
a natural disaster is an event of nature that takes human lives or destroys property.
types of natural disaster
weather conditions blizzard, cyclone, hurricane, tornado.
floods and their prevention.
earthquakes.
fires and fire prevention.
volcanic eruption.
outbreaks of disease plague, epidemiology.


earthquakes

an earthquake is the shaking of the earths surface caused by rapid movement of the earths rocky outer layer. earthquakes occur when energy stored within the earth, usually in the form of strain in rocks, suddenly releases. this energy is transmitted to the surface of the earth by earthquake waves.
the destruction an earthquake causes depends on its magnitude and duration, or the amount of shaking that occurs. the size varies from small, imperceptible shaking to large shocks felt over thousands of kilometres. earthquakes can deform the ground, ma...