Plate tectonics

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Plate tectonics (from the Greek τέκτων; tektōn, meaning "builder" or "mason") describes the large scale motions of Earth's lithosphere. The theory encompasses the older concepts of continental drift, developed during the first decades of the 20th century by Alfred Wegener, and seafloor spreading, understood during the 1960s.

The lithosphere is broken up into what are called tectonic plates. In the case of Earth, there are currently eight major and many minor plates (see list below). The lithospheric plates ride on the asthenosphere. These plates move in relation to one another at one of three types of plate boundaries: convergent, or collisional boundaries; divergent boundaries, also called spreading centers; and transform boundaries. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries. The lateral movement of the plates is typically at speeds of 50–100 mm annually.

For more information about Plate tectonics, read the full article at Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.

News tagged with tectonic plates

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Tremors between slip events: More evidence of great quake danger to Seattle

Space & Earth / Earth Sciences

Dec 15, 2009 | 4.4 / 5 (7) | 0

(PhysOrg.com) -- For most of a decade, scientists have documented unfelt and slow-moving seismic events, called episodic tremor and slip, showing up in regular cycles under the Olympic Peninsula of Washington state and Vancouver ...

From greenhouse to icehouse -- reconstructing the environment of the Voring Plateau

Space & Earth / Earth Sciences

Dec 15, 2009 | 4.1 / 5 (7) | 1

The analysis of microfossils found in ocean sediment cores is illuminating the environmental conditions that prevailed at high latitudes during a critical period of Earth history.

New Technology Allows Geophysicist To Test Theory About Formation of Hawaii (w/ Podcast)

Space & Earth / Earth Sciences

Dec 11, 2009 | 4.3 / 5 (4) | 1

(PhysOrg.com) -- If you've ever been to Hawaii, you probably spent your time enjoying the scenery of the beautiful islands, rather than wondering how they got to be there in the first place. But that's just what scientists ...

Superior Super Earths

Space & Earth / Space Exploration

Nov 30, 2009 | 4.6 / 5 (55) | 15

Super Earths are named for their size, but these planets - which range from about 2 to 10 Earth masses - could be superior to the Earth when it comes to sustaining life. They could also provide an answer to ...

New study cites lower rate of quakes along some subduction zones

Space & Earth / Earth Sciences

Dec 04, 2009 | not rated yet | 0

Most earthquakes occur along fault lines, which form boundaries between two tectonic plates. As the relative speed of the plates around a fault increases, is there a corresponding increase in the number of earthquakes produced ...