One of the most destructive phenomena of nature is a severe earthquake and its terrible effects. In many regions of America the word “tremor” is used to refer to a lower intensity movement, and the word “earthquake”, to a higher. An earthquake is a sudden movement of the Earth, caused by the abrupt release of strain when the tectonic plates move looking for the balance.CAUSES
The principal cause of an earthquake is the tectonic plate and the volcanic activity. The tectonic earthquakes are closely related to the formation of geological faults. These tremors often occur at the end of a cycle known as “Seismic Cycle”, that is the period of time in which the deformation is accumulated in the deepest place of the Earth, and at the end of the cycle, this deformation is suddenly released. That release is the phenomenon known as earthquake. When the earthquake happens, the deformation begins to accumulate again.
The deepest place of the Earth in which the tremor occurs, is known as Hypocenter, and the superficial place that is affected by the jolt is known as Epicenter. The seismic movement is propagated by elastics waves (similar to the sound) in a vertical way starting in the Hypocenter. There are three types of seismic waves, two of them occur just inside of the Earth, and the another one refers to the superficial waves that cause the destruction of works and loss of human lives.
EFFECTS
Shaking and ground rupture are the main effects created by earthquakes, principally resulting in more or less damage to buildings or other rigid structures. The severity of the local effects depends on the complex combination of the earthquake magnitude, the distance from epicenter, and the local geological conditions, which may amplify or reduce wave propagation. Earthquakes can cause landslides and avalanches, which may cause damage in hilly areas. Also fires can be generated by break of the electrical power or gas lines. About human impacts, earthquakes may result in disease, lack of basic necessities and loss of life, higher insurance premiums, general property damage, road and bridge damage, and collapse of buildings or destabilization of the base of buildings which may lead to collapse in future earthquakes.
POSSIBLE PREVENTION
Though it is not possible to predict when an earthquake can occur, in some regions certain precursor phenomena take place. Among these phenomena we can mention the underground noises, the variations of the water level of the wells, the overheating of the soil, the atmospheric disturbances and the agitation that many domestic animals demonstrate.
