Types of destructions caused by earthquakesArticles > Types of destructions caused by earthquakes
Earthquakes are natural activities, which do not directly kill the animals, plants, and human beings, but earthquakes become lethal when the man-made structures fail to survive earthquakes. Earthquakes bring a lot of changes to the earth's crust and affect the biosphere of the earth, therefore, we can not deny the hazardous nature of earthquakes. Earthquakes cause the following types of damages and changes to the landscape.
(1). Expansion of Earth's crust
(2). Contraction of Earth
(3). Disturbance of natural and man-made drainage system
(4). The eruption of the Mud-volcanoes
(5). Damage to the cultural landscape
(6). Causing landsliding
(7). Break out of the fires and electric shortcircuits
(8). Liquefaction, Subsidence, and Related Effects
(1). Expansion of Earth's crust:
Earth's crust is moved as a result of the earthquake. The violent to-and-fro motion of the crust causes the formation of cracks or faults planes, which bring changes both below and above the surface of Earth. The displacement can be vertical or horizontal in the shape of fault terrace, fault scarp, or fault plane. In the case of the creation of a fault, its effect is visible at the surface in the form of a fault scarp. A fault scarp is an exposed cliff-shaped face of a fault plane. The lower edge of the fault scarp is called a fault terrace. A band of crushed rock pieces called fault breccia, which lies along the trace.
(2). Contraction of Earth:
On one hand, the longitudinal or the secondary earthquake wave makes the earth's crust expand, while on the other hand they the primary waves or the compressional waves result in compression/ contraction of the crust. This happens, when the ends of joints of the faults come closer to each other. The trenches are filled due to the compressional movement due to the earth. The compressional activity makes the water and fuel mains collapse. Water and fuel leak and accumulates in the populated areas, which can be hazardous in the form of contagious disease and the breaking out of fires.
(3). Disturbance of drainage system:
The purpose of the drainage system is to sewer the wasted material along with the wasted water. There are two types of drainage systems; the natural and the artificial. The natural drainage system drains out the rainwater to the low lying areas. The purpose of the natural drainage system is only to spread water all around the globe to meet the need of plants and animals. The purpose of the artificial or cultural drainage system is to drain-away dirty and contaminated water away from the populated areas to escape the human habitats from their unhealthy effects. The natural disastrous activities like storms and earthquakes bring destructive changes within the ongoing drainage system. Sometimes, due to the landslides, the streams are completely blocks, and a dam is formed. The stream water starts accumulating in the naturally built dam. As a load of water in the weak dam increases, it happens to collapse suddenly, thus releasing a huge amount of water. The collapse of the dam is very disastrous for the nearby population. Moreover, the earthquakes collapse the urban drainage system, by means of contracting and expanding the earth's surface. Sometimes the mains of drinking water and gas and oil intermix. The contaminated water becomes unhygienic and may result in some contagious diseases like Cholera. Similarly, in many cases, springs of water erupt out, whereas embankments of lakes are drained away at some places. For example, the Lungarno Pacnotti in Pisa (Italy) dropped nine feet creating deep crevices on the road as a result of an earthquake.
(4). Mud Volcanoes:
Sometimes, due to the intense ground shaking the underground water channels gets blocked, and the water of aquifers is gushed forth in the form of a water jet, which gathers mud and sand at their mouths. Subsequently, the mud is compiled and rises high and adopts the shape of a cone, which is known as a mud volcano.
(5). Damage to the Cultural Landscape:
An earthquake offsets the linear features like roads, hedges, pipelines, electricity poles, telephone connections, and other structures nearby the tall buildings. The collapse of the tall buildings also results in the collapse of the cultural landscape. Electric shocks, road blockage, and leakage of mains are very often during an earthquake. An earthquake somehow hinders life activities at all costs.
The shaking of unstable slopes and the rupture of the earth's surface/ground during an earthquake results in lethal land sliding. The landslide blocks can easily block the roads and damage buildings in their way. They can also block and damage the railway tracks. Sometimes the hilltop homes also slide down along with the earthen sliding material. slide land bulks can easily destroy buildings and paths in their way.
An earthquake is an underground seismic activity, which shakes the earth's crust, especially the denser crust. If the oceanic crust is compared with the continental crust, the oceanic crust is denser than the continental crust. In a denser medium, the seismic waves travel faster and intensively. When an earthquake happens underwater, the shaking activity gives birth to very high tides within the sear water. A tsunami that is misconcepted as the tidal waves (regular waves) is a catestrophic grave hazard in many coastal regions of the world, especially around the Pacific Ocean basin, is caused by underwater seismic activity. The shaking seafloor cause these hazardous waves in the seawater, which completely erase the coastal civil and other structures. The velocity of a tsunami wave may exceed 700 km/hour, and its height may cross 27 meters.
Earthquake becomes more disastrous when a fire breaks resultantly.0 Ground rupture, subsidence, and liquefaction may collapse the oil and gas mains. The leaked fuel by grinding underground material can catch fire. In many cases, electricity wires produce sparks that ignite the leaked gas and oil. The earthquake of Northridge is an example of a catastrophic result of the earthquake in the form of fire.
(9). Liquefaction, Subsidence:
As a result of an earthquake, the upper solid hard crust gets mixed with the lower aquifers. The mixing of the soil and sand in water is known as liquefaction. Subsidence is the result of liquefaction, which means the sinking of the solid material into the liquid. When the ground as a result of liquefaction and subsidence becomes soft, buildings or their parts get sink into the ground. This is a very dangerous situation in many soft soiled regions.
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