1.0 Topic Definition Plate tectonics is a scientific theory that studies how Earth's plates are guided and shaped by geological forces to keep them in constant motion. The theory explains the Earth's current tectonic behavior, in particular the global distribution of mountain formation, seismic activity and volcanism in a series of linear belts. (Pitman, WC, 2007) Plate tectonics explains geomagnetic and geothermal phenomena, magma and orogeny, and elucidates global mid-ocean ridges and rift system, etc. The theory also analyzes geological questions such as the origin of oceanic crust. Plate tectonics has a significant effect on all fields of geology because it helps explain many geological phenomena.Figure1. Earth Plate2.0 History Way back in 1915, scientist Alfred Wegener proposed his theory of "continental drift", which clarified that continents furrowed the crust of ocean basins. It helped explain why the contours of many coastlines, such as those of South America and Africa, looked like a puzzle when they fit together. However, Wegner's theory was controversial because it lacked an explanation for why the continents moved. In 1929, Arthur Holmes elaborated one of Wegner's hypotheses: the mangle undergoes thermal convection. In the early 1960s Holmes' idea aroused many attractions. Harry Hess and R. Deitz developed a similar hypothesis, known as “seafloor spreading.” In 1965, JT Wilson proposed a new theory, which was “Plate Tectonics”. In 1967, Xavier Le Pichon published a complete model based on 6 major plates with their relative movements, which perfected the theory of "Plate Tectonics". He also explained the principle of movement of the plates.3.0 Science Organiz...... half of the paper...... http://www.wadsworthmedia.com/marketing/sample_chapters/0495011487_ch02.pdf [Accessed on August 29 , 2011]Plate Tectonics, Cotf [online] Available at: http://www.cotf.edu/ete/modules/msese/earthsysflr/plates1.html [Accessed 29 August 2011]Nelson, S.A. (2003) Global Tectonics , Tulane.edu [online] Available at: http://www.tulane.edu/~sanelson/geol111/pltect.htm [Accessed September 9, 2011] Richer Scales Measures in Earthquakes (2011), Weegy [online ] Available at: http://www.weegy.com/home.aspx?ConversationId=E0B052FE [Accessed September 9, 2011] Earthquake Measurement Scales (1999), Matter [online] Available at: http: //www.matter.org. uk/schools/content/Seismology/richterscale.html [Accessed 29 August 2011]Understanding Plate Motions (1999), USGS [online] Available at: http://pubs.usgs.gov/gip/dynamic/understanding .html [ Accessed August 29, 2011]