| An Earthquake is a sudden movement of the ground | | | | ones are caused due to human activities, like pumping |
| that releases the elastic energy stored within the | | | | fuels deep into the earth or due to explosives, and |
| rocks, creating destructive seismic waves. The word | | | | several other reasons. |
| "seismic" comes from the Greek word "seismos" | | | | MEASUREMENT OF EARTHQUAKES: |
| meaning an earthquake. These quakes are not isolated | | | | The most popular scale used to measure earthquakes |
| events. They come with smaller shocks, called | | | | is the Richter scale, named after Charles Francis |
| aftershocks, with smaller effects. | | | | Richter (US).This scale measures the energy released |
| An earthquake is caused when two sides of a large | | | | at the focus of the quake, read through a seismograph |
| fracture in the rocks within the earth slide past each | | | | which gives the direction and force of the quakes. An |
| other. This fracture is called a fault, which may be | | | | earthquake of size 8 is 10 times more devastative |
| microscopic or thousands of kilometers in length, while | | | | than size 7, 100 times more destructive than 6, and so |
| their width is usually a few millimeters or a few meters | | | | on. the frequency of earthquakes decreases as the |
| in size.The size of an earthquake depends on the area | | | | magnitude increases, as the earth experiences about |
| of the fault that ruptured, and the distance through | | | | 800 earth quakes of size 5-6 , but only one or two |
| which the rocks on the two sides of the fault slide | | | | quakes of size 8-9. |
| past one another.Small earth quakes are caused by | | | | EARTHQUAKE EFFECTS: |
| small faults or small parts of big faults. These last only | | | | Earthquakes cause great loss of life by causing |
| for a fraction of a second and usually unnoticed, as | | | | damage to buildings, bridges, dams, etc. they can |
| the rocks on either side of the faults are not displaced | | | | trigger devastating landslides. Fires can begin due to |
| much. The larger ones are caused due to faults which | | | | leaks in Gas plants and electrical lines. Earth quakes |
| are tens to thousands of kilometers long, taking | | | | can also generate tidal waves, or the tsunamis, |
| minutes and the displacement of the rocks is around | | | | capable of destroying entire townships. These quakes |
| tens of meters. | | | | also cause liquefaction of soils, which makes soil lose |
| Earthquakes are caused because the earth is regularly | | | | almost all its strength, which makes it function like |
| cooling since it was born, the seismic wave being one | | | | quicksand. This material is capable of swallowing an |
| of its ways to release the elastic energy. | | | | entire building within itself. |
| Earthquakes are generally categorized into three | | | | Earthquakes around the world cost around 15,000 lives |
| types: Tectonic, Volcanic and Artificial. | | | | per year. Several countries like the United States of |
| Tectonic earth quakes are the most devastating, and | | | | America, China, Japan and Russia are most actively |
| unfortunately the most unpredictable. The volcanic | | | | participating in seismological research, trying to predict |
| quakes are seldom important or devastative, but they | | | | future earthquakes. |
| help predict the eruption of volcanoes. The artificial | | | | |