Earthquakes: What's actually shaking?!
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What's an earthquake and what causes them? |
Tectonic plates are large solid rocks located at the bottom of the earth's crust and the outer most part of the mantle. They are continuously moving at a slow pace in different directions. The plates and the outer layer of the crust make up the lithosphere ("Earthquake", 5 April 2013). The plates are like linings which support the land we live on and the ocean floor. There are currently twenty tectonic plates which float on the sphere just below the crust called the mantle. The plates are up to 100 km thick in the continental plates and about 5 km thick in the oceanic plates. The oceanic plates are denser, made of basaltic rocks because the ocean floor is compressed by the heavy seawater. The continental plates are more brittle and made mostly of granite ("Earthquake", 5 April 2013). For more information on tectonic plates, click on the Earthquake Zones page.
The mantle, beneath the earth's crust, are fluid and continuously circulating ("Earthquake", 5 April 2013). The Theory of Plate Tectonics supports the idea that the mantle's circulation, propelled by convection currents slowly moves the tectonic plates in the crust ("Mantle Convection", 2013). The outer most layer of the mantle is called the asthenosphere. It is ductile, soft clay like, in consistency with chunks of rocks from the crust embeded in it. The asthenosphere moves because of the churning motion in the inner mantle and outer core beneath it. This movement, the convection current, is powered by the heat generated by the radioactive solid iron inner core. The high temperature of the earth liquefies the content of the outer core and turns it into magma. The inner mantle consists of liquid molten lava ("Plate Tectonics", 30 April 2013). In the outer part of the mantle, warmer pieces of rocks rise while cooler rocks sinks. This action of the rocks churns the molten lava. Basically, the tectonic plates are surfing on the moving mantle. It is no wonder the plates collide from time to time. See the attached animation link below to understand how the tectonic plates move. https://www.dropbox.com/s/onvamuj56xkrkxi/Aya_Earthquakes%20.M4V earthquake's master pieces: geological effects on the crustEarthquakes occur and leaves behind permanent geological changes on the earth's crust. They speed up the movement of the tectonic plates, create amazing fault lines, build and destroy mountains on land and in the ocean and create or destroy water systems (Franklin Institute, 2013). See the tutorial video below on how earthquakes cause changes on the earth's crust.
For more information and images, click on the Geological Effects. |
Earthquakes are one of the factors causing permanent changes to the earth's crust. An earthquake is the shaking of the ground when the tectonic plates, which is part of the earth's crust slides or collides up against each other. It is a result of a sudden release of seismic energy fom the earth's crust (George, 2013). Earthquakes can occur anywhere on earth where strained energy is collected along fault lines where tectonic plates meet ("Earthquakes", 5 April 2013). Plates are constantly moving at a very slow pace. When the plates converge or diverge, huge rocks from the edges of the plates shifts or breaks with great force and shakes the earth.
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Reference &sources
Works Cited
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