my fwenz

myself

NATURAL DISASTER

A natural disaster is the effect of a natural hazard (e.g., flood, tornado, hurricane, volcanic eruption, earthquake, or landslide). It leads to financial, environmental or human losses. The resulting loss depends on the vulnerability of the affected population to resist the hazard, also called their resilience.^[1] This understanding is concentrated in the formulation: "disasters occur when hazards meet vulnerability."^[2] A natural hazard will hence never result in a natural disaster in areas without vulnerability, e.g. strong earthquakes in uninhabited areas.^[3

An earthquake is a sudden shake of the Earth's crust caused by the tectonic plates colliding. The vibrations may vary in magnitude. The underground point of origin of the earthquake is called the "focus". The point directly above the focus on the surface is called the"epicenter". Earthquakes by themselves rarely kill people or wildlife. It is usually the secondary events that they trigger, such as building collapse, fires, tsunamis (seismic sea waves) and volcanoes, that are actually the human disaster. Many of these could possibly be avoided by better construction, safety systems, early warning and evacuation planning.Earthquakes are caused by the discharge of energy accumulated along geologic fault.

Volcanoes can cause widespread destruction and consequent disaster through several ways. The effects include the volcanic eruption itself that may cause harm following the explosion of the volcano or the fall of rock. Second, lava may be produced during the eruption of a volcano. As it leaves the volcano the lava destroys any buildings and plants it encounters. Third, volcanic ash generally meaning the cooled ash - may form a cloud, and settle thickly in nearby locations. When mixed with water this forms a concrete-like material. In sufficient quantity ash may cause roofs to collapse under its weight but even small quantities will harm humans if inhaled. Since the ash has the consistency of ground glass it causes abrasion damage to moving parts such as engines.

Blizzards are severe winter storms characterized by low temperature, strong winds, and heavy snow. The difference between a blizzard and a snow storm is the strength of the wind. To be a considered a blizzard, the storm must have winds in excess of 35 miles per hour, it should reduce the visibility to 1/4 miles, and must last for a prolonged period of 3 hours or more. Ground blizzards require high winds to stir up snow that has already fallen, rather than fresh snowfall. Blizzards have a negative impact on local economics and can terminate the visibility in regions where snowfall is rare.