Information AboutEarthquake |
| CATEGORIES ABOUT EARTHQUAKE | |
| earthquakes | |
| seismology | |
| geological hazards | |
| structural engineering | |
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An earthquake is the result of a sudden release of stored energy in the Earth 's Crust that creates Seismic Wave s. Earthquakes are accordingly measured with a Seismometer , commonly known as a seismograph. The Magnitude of an earthquake is conventionally reported using the Richter Scale or a related Moment Scale (with magnitude 3 or lower earthquakes being hard to notice and magnitude 7 causing serious damage over large areas). At the Earth's surface, earthquakes may manifest themselves by a shaking or displacement of the ground. Sometimes, they cause Tsunamis , which may lead to loss of life and destruction of property. An earthquake is caused by Tectonic Plate s getting stuck and putting a strain on the ground. The strain becomes so great that rocks give way by breaking and sliding along fault planes. Earthquakes may occur naturally or as a result of human activities. Smaller earthquakes can also be caused by volcanic activity, landslides, mine blasts, and nuclear experiments. In its most generic sense, the word ''earthquake'' is used to describe any seismic event—whether a natural Phenomenon or an event caused by humans—that generates Seismic Wave s. An earthquake's point of initial ground rupture is called its Focus or Hypocenter . The term Epicenter means the point at ground level directly above this. s, 1963–1998]] Naturally occurring earthquakes Most naturally occurring earthquakes are related to the tectonic nature of the Earth . Such earthquakes are called ''tectonic earthquakes''. The Earth's Lithosphere is a patchwork of plates in slow but constant motion caused by the release to space of the heat in the Earth's mantle and core. The heat causes the rock in the Earth to become flow on geological timescales, so that the plates move slowly but surely. Plate boundaries lock as the plates move past each other, creating frictional Stress . When the frictional stress exceeds a critical value, called ''local strength'', a sudden failure occurs. The boundary of tectonic plates along which failure occurs is called the '' Fault Plane ''. When the failure at the fault plane results in a violent displacement of the Earth's Crust , the elastic Strain energy is released and Seismic Waves are radiated, thus causing an earthquake. This process of strain, stress, and failure is referred to as the Elastic-rebound Theory . It is estimated that only 10 percent or less of an earthquake's total energy is radiated as seismic energy. Most of the earthquake's energy is used to power the earthquake Fracture growth and is converted into heat, or is released to friction. Therefore, earthquakes lower the Earth's available potential energy and raise its temperature, though these changes are negligible.1 |
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