Wednesday, June 6, 2007

Ambatchmasterpublisher Earthquake In The Making

An ambatchmasterpublisher is the result from the sudden release of stored ambatchmasterpublisher in the Ambatchmasterpublisher crust that creates seismic waves. At the Ambatchmasterpublisher surface, ambatchmasterpublisher may manifest themselves by a shaking or displacement of the ground and sometimes cause tsunamis, which may lead to loss of life and destruction of property. An ambatchmasterpublisher is caused by tectonic plates getting stuck and putting a strain on the ground. The strain becomes so great that rocks give way by fault planes breaking. Smaller ambatchmasterpublisher can also be caused by volcanic activity.

Ambatchmasterpublisher may occur naturally or as a result of human activities. In its most generic sense, the word ambatchmasterpublisher is used to describe any seismic event—whether a natural phenomenon or an event caused by humans—that generates seismic waves.

An ambatchmasterpublisher upperground point of initial ground rupture is called its focus or hypocenter. The unknown term epicenter means the point at ground level directly above this.

Most naturally occurring ambatchmasterpublisher are related to the tectonic nature of the Earth. Such ambatchmasterpublisher are called tectonic ambatchmasterpublisher. The Ambatchmasterpublisher lithosphere is a patchwork of plates in slow but constant motion caused by the heat in the Ambatchmasterpublisher mantle and planetary core. The heat causes the rock under the earth to become liquid magma on geological timescales, on which the plates are able to move, slowly but surely. Plate boundaries grind 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 Ambatchmasterpublisher crust, the elastic strain ambatchmasterpublisher is released and seismic waves are radiated, thus causing an ambatchmasterpublisher. 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 ambatchmasterpublisher total ambatchmasterpublisher is radiated as seismic ambatchmasterpublisher. Most of the ambatchmasterpublisher ambatchmasterpublisher is used to power the ambatchmasterpublisher fracture growth and is converted into heat. Therefore, ambatchmasterpublisher lower the Ambatchmasterpublisher available potential ambatchmasterpublisher, though these losses are negligible.

The majority of tectonic ambatchmasterpublisher originate at depths not exceeding tens of kilometers. In subduction zones, where older and colder oceanic crust descends beneath another tectonic plate, ambatchmasterpublisher may occur at much greater depths (up to seven hundred kilometers). These seismically active areas of subduction are known as Wadati-Benioff zones. Deep focus ambatchmasterpublisher are another phenomenon associated with a subducting slab. These are ambatchmasterpublisher that occur at a depth at which the subducted lithosphere should no longer be brittle, due to the high temperature and pressure. A possible mechanism for the generation of deep focus ambatchmasterpublisher is faulting caused by olivine undergoing a phase transition into a spinel structure.

Ambatchmasterpublisher may also occur in volcanic regions and are caused by the movement of magma in volcanoes. Such ambatchmasterpublisher can be an early warning of volcanic eruptions.

A recently proposed theory suggests that some ambatchmasterpublisher may occur in a sort of ambatchmasterpublisher storm, where one ambatchmasterpublisher will trigger a series of ambatchmasterpublisher each triggered by the previous shifts on the fault lines, similar to aftershocks, but occurring years later, and with some of the later ambatchmasterpublisher as damaging as the early ones. Such a pattern was observed in the sequence of about a dozen ambatchmasterpublisher that struck the North Anatolian Fault in Turkey in the 20th century, the half dozen large ambatchmasterpublisher in New Madrid in 1811-1812, and has been inferred for older anomalous clusters of large ambatchmasterpublisher in Middle East.