An earthquake is basically a shaking of the earth caused by seismic waves that result from energy suddenly released in the earth’s crust. An earthquake whose epicenter is located offshore causes a tsunami. In some cases earthquakes may trigger volcanic activity and landslides. Earthquakes are fatal natural phenomena since they result in the displacement of ground collapsing anything on it.
Types of earthquakes
There are four main types of earthquakes. They include volcanic earthquakes, collapse earthquakes, explosion earthquakes and tectonic earthquakes which are most common.
Tectonic earthquakes occur when tectonic plates slide over each other causing a huge tremor. Tectonic plates are able to move slowly and sometimes may collide or move past each other; however, sliding over each other causes a tremor which results in an earthquake. Their magnitude may vary from extremely high to low. They have been the cause of mass destruction often times in the past and have been the most commonly experienced all over the world. Most tectonic earthquakes are of high magnitude and hence very destructive.
Volcanic earthquakes which do not occur as frequently as tectonic earthquakes occur after or just before a volcanic eruption. Volcanic earthquakes occur in two types namely long period volcanic earthquakes and tectonic volcano earthquakes. Volcano tectonic earthquakes usually occur after a volcanic eruption. After a volcanic eruption magma that erupts from under the ground leaves a void and as the rocks move to fill the void they displace the ground causing a great earthquake. It may also be the result of lave that blocks its vent during a volcanic activity trapping high pressure air inside. Eventually this pressure releases causing a great explosion that often results in high magnitude severe earthquakes. Long period volcanic earthquakes usually occur after a volcanic eruption. They occur due to change in the temperature of the magma below the surface of the earth creating seismic waves that cause an earthquake.
Collapse earthquakes are perhaps the least severe of all the types of earthquakes. Due to the nature of their occurrence which takes place in mines they are sometimes known as mine bursts. They occur due to pressure that is induced within the rocks on the roof of a mine. This causes the roof to collapse causing tremors on the ground adjacent to the mines. These however are experienced as not so severe shaking of the ground by adjacent locations.
Explosion earthquakes as opposed to the other types of earthquakes resulting from natural causes are caused by human activity. They occur due to nuclear explosions. They are a direct effect of nuclear wars. During nuclear explosions a lot of energy is released within the earth and its pressure eventually exceeds that of the atmosphere resulting in a great explosion.
Earthquakes are one of the most fatal natural disasters and often result in injury whose extent depends on the earthquake’s magnitude. The magnitude of an earthquake is measured using a seismograph. Usually the likelihood of an earthquake occurring in a certain place can be measured. However it is difficult to predict when exactly an earthquake will take place. Apart from the type of earthquake that is a result of human activity other types of earthquakes cannot be prevented. They are purely a result of nature and natural geographic activity. However in spite of being impossible to stop, the likelihood of their occurrence more often than not can be predicted and the people living in the vicinity of such areas warned well in advance.