Earthquake: Causes, Effects and Magnitude measurement
An earthquake is a sudden shaking of the surface of the earth by the passage of the seismic waves through Earth’s rocks. It is also known as tremblor, tremor or quake. Let us tell you that just below the earth's surface where earthquakes start is called hypocenter and just directly above the surface of the earth is called epicentre?
Size of an earthquake may differ and sometimes it is said that weak earthquakes are not felt also but the violent one may cause destruction and may destroy whole cities. It all depends upon the frequency, type and size of the earthquake experienced over a period of time. It is measured on Richter’s scale.
How are earthquakes measured?
The vibrations caused by an earthquake are detected by a seismometer and on a seismograph, it plots these vibrations. Richter scale also measured the strength or magnitude of an earthquake. When an earthquake measured around 7 or 8 on the Richter scale, it can be devastating.
What causes an Earthquake?
When there is sudden movement on the Earth's crust, earthquakes occur. Earthquakes are caused due to sudden lateral or vertical movements in the crust of the Earth. Or we can say that when tectonic plates ride over the other and cause the collision of orogeny or mountain building. The largest faults are formed on the surface of the Earth due to boundaries between moving plates. When there is relative motion between the plates, it is more severe. Circum-Pacific Belt is the most important earthquakes belt which affects several populated coastal regions around the Pacific Ocean like New Zealand, New Guinea, and Japan, etc. It is estimated that the energy about 80% is released in the earthquakes that come from those whose epicentres are in this belt.
Let us tell you that when the friction overcomes by mechanical stresses, the rocks slip and releases vast amounts of energy and is known as an earthquake. When there is motion between the plates, the stress increases and if it continues allows sliding over the locked portion of the fault and releases the stored energy as shock waves. In Rift valley, Africa such types of faults are seen known as Andreas fault in San Francisco.
Types of Earthquakes
Mainly, there are four types of earthquakes namely tectonic, volcanic, collapse and explosion.
Tectonic earthquake: This occurs when due to geological forces on rocks and the adjoining plate’s cause’s physical and chemical change and results in the breaking of the Earth's crust.
Volcanic earthquake: Results from tectonic forces and occurs in conjunction with volcanic activity.
Collapse earthquake: are generally small earthquakes that occur in underground caverns and mines caused by the seismic waves which are produced from the explosion of rock on the surface.
Explosion earthquake: Occur due to the detonation of a nuclear or chemical device.
We all know that the effects of an earthquake are terrible and devastating. Several buildings collapsed, schools, hospitals, a whole city may be destroyed due to it. A lot of people get killed and injured. Various people lose their property and money. It not only affects the health of the people but emotionally also make weak.
Some environmental effects occur due to the earthquake are surface faulting, tectonic uplift and subsidence, tsunamis, soil liquefaction, ground resonance, landslides, etc. are linked to the tremblors or due to the shaking of the ground.
Hoping that you will come to know about the earthquake, how it occurs and its effects.