Wednesday, August 25, 2010

How Do Natural Disasters Occur

Earthquakes


Earthquakes might be the king of the natural disasters. With their sheer force, they can destroy buildings, lives and man-made structures. Earthquakes are formed along fault lines, or the areas where tectonic plates meet underground. Occasionally, these plates shift, causing an enormous burst of energy that causes the ground above to shake violently. The plates rub up against each other, causing tension. When the rock breaks between them, allowing the plates to actually move, this is when the full-scale earthquake occurs. The earthquake ends when the plates catch on unbroken rock once again, and they settle.


Tornadoes


Tornadoes are usually formed in the middle of thunderstorms. Much like earthquakes, it is difficult to predict when and where a tornado will strike. While a severe thunderstorm may prompt meteorologists to issue a tornado watch, this is mostly guesswork based on the correct conditions. These conditions include warm air meeting a front of cool, dry air. When this happens, instability occurs in the atmosphere. The wind changes directions and these air masses rise high into the sky, twirling the entire way and forming a tornado. They usually last only a few minutes, but during that time the wind speed is such that they can cause serious damage, if only to a very localized area.


Hurricanes


Hurricanes, or tropical cyclones as they are called in the scientific community, are perhaps capable of the most widespread damage and destruction of any natural disaster. On the other hand, we are able to spot hurricanes well in advance, giving people time to prepare for the worst. Hurricanes typically form in the warm waters off the coast of Africa. Warm air rises to the sky, creating a low-pressure situation below. When this happens, more warm air rushes in to fill that low-pressure area, and the same thing happens to it. An endless cycle is created, all of the wind rising and swirling and growing with nothing much to stop it (unless it hits land). Typically, the warmer the waters, the more powerful a hurricane has the potential to become.







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