1.0 Topic Definition Plate Tectonics is a scientific theory which study how the Earth’s plates are driven and shaped by geological forces to keep them in constant movement. The theory explains the present-day tectonic behavior of the Earth, particularly the global distribution of mountain building, earthquake activity, and volcanism in a series of linear belt. (Pitman, W.C., 2007) Plate Tectonics explains geomagnetic and geothermal phenomena, magma and orogenesis, and it clarify the global mid-ocean ridges and rift system, etc. The theory also analyzes geological issues such as the origin of oceanic crust. Plate Tectonics has a significant effect on all fields of geology because it helps explain many geological phenomenons. Figure1. Earth Plate 2.0 History Way back to 1915, scientist Alfred Wegener proposed his theory of “Continental Drift”, which clarified that the continents plowed through crust of ocean basin s. It helped explain why the outlines of many coast lines, such as South America and Africa looked like a puzzle when they fitted together. However, Wegner’s theory was controversial because it lacked of explanation of why continents moved. In 1929, Arthur Holmes elaborated on one of Wegner’s hypotheses: the mangle undergoes thermal convection. In the early of 1960s, Holmes’ idea received many attractions. Harry Hess and R. Deitz developed a similar hypothesis, known as “Sea floor spreading”. In 1965, J.T. 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 motions, which refined the theory of “Plate Tectonics”. He also explained the principle of the movement of the plates. 3.0 Science Organiz... ... middle of paper ... ... http://www.wadsworthmedia.com/marketing/sample_chapters/0495011487_ch02.pdf [Accessed August 29, 2011] Plate Tectonics, Cotf [online] Available at: http://www.cotf.edu/ete/modules/msese/earthsysflr/plates1.html [Accessed August 29, 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] Scales for measuring earthquakes (1999), Matter [online] Available at: http://www.matter.org.uk/schools/content/Seismology/richterscale.html [Accessed August 29, 2011] Understanding Plate Motions (1999), USGS [online] Available at: http://pubs.usgs.gov/gip/dynamic/understanding.html [Accessed August 29, 2011]
Earthquakes are a natural part of the Earth’s evolution. Scientific evidence leads many geologists to believe that all of the land on Earth was at one point in time connected. Because of plate tectonic movements or earthquakes, continental drift occurred separating the one massive piece of land in to the seven major continents today. Further evidence supports this theory, starting with the Mid-Atlantic ridge, a large mass of plate tectonics, which are increasing the size of the Atlantic Ocean while shrinking the Pacific. Some scientists believe that the major plate moveme...
Earthquakes play a major role into understanding the composition and materials that exist within the Earth (Merali and Skinner, 2009, p.252). Earthquakes are the main source of insight into the inner workings of the earth, due to the nature of the seismic waves they produce. P and S waves are reflected and refracted at different boundaries within the earth, and this enables seismologists to make inferences about the internal composition and structural of planet Earth. (Merali and Skinner, 2009, p.252).
Seismic studies show that the mid-oceanic ridges experience an elevated number of earthquakes. All these observations indicate intense geological activity at the mid-oceanic ridges. Periodically, the Earth's magnetic field reverses. New rock formed from magma records the orientation of Earth's magnetic field at the time the magma cools. Study of the sea floor with magnetometers revealed "stripes" of alternating magnetisation parallel to the mid-oceanic ridges.
About 20 million years ago the last part of the Farallon sea floor plate subducted under the North American plate. This put the North American plate and the Pacific plate into contact, but unlike the Farallon sea floor plate, the Pacific plate sheared against the side of the North American plate. Because there was no plate subducting, the North American plate was in direct contact with the mantle (Tierney, 29). Heat from the mantle made the continental crust more ductile, which allowed the crust to extend and thin.
Back then, no one understood how or why the two rocks were next to each other until around 40 years ago when the theory of plate tectonics was introduced. The purpose of the tectonic theory was to explain the process of earthquakes, not just around the San Andreas Fault, but also on the others that ran concurrent to it.
Heller, Arnie. "The 1906 San Francisco Earthquake." Science & Technology (2006): 4-12. Web. 8 May 2014.
From studying the science behind the San Francisco earthquake, scientists have made a number of important discoveries involving how earthquakes function. At 5:12 on a fateful April morning in 1906, the mammoth Pacific and North American plates sheared each other at an incredible twenty-one feet along the San Andreas fault, surpassing the annual average of two inches (“San Francisco Earthquake of 1906”) (“The Great 1906 Earthquake and Fires”). A few seconds later, the destructive earthquake occurred. The ground shifted at almost five feet per second, and the shaking could be felt all the way from southern Oregon to southern Los Angeles to central Nevada (“Quick”) (“The Great 1906 San Francisco Earthquake”). In fact, the earthquake could be registered in a seismograph on Capetown, South Africa, an astounding 10,236 miles away...
Before examining the Northridge event, understanding the naturally occurring hazard that is an earthquake will help to better understand exactly what happened and why it was such an important geological event. With four distinct layers, two layers, the crust and upper portion of the mantle, compose the skin that is the surface layer of the Earth. The crust is not a single, continuous piece. It is actually several different pieces, or plates, that come together to form the puzzle that comprises the surface of the Earth. These plates are in constant motion rubbing against one another. These areas, known as fault lines, where the plates rub up against one another have spots where one plate ”gets stuck while the rest of the plate keeps moving. When the plate has moved far enough, the edges unstick and is how most of the earthquakes around the world occur” (Wald, 2012). The energy stored from the friction of the two plate...
benchmark for the future, and integrated investigation into the effects of earthquakes in the U.S.
there were many specific scientists that contributed to this idea of the moving continents, some more than others. 2 major contributors to the idea were Alfred Wegener, and Henry Hess. They all contributed to the idea of why the plates are in different place that when the Earth was first born. One of the Scientists, Alfred Wegener, is very well known and his name is related when talking about Plate tectonics. When he first proposed( put out there) his theory ( which later turned out to be right) it was rejected immensely because he did not know how or why the continents moved.
...a great deal of concrete results. The Magnetischer Verein and its journal were conceived, and the atlas of geomagnetism was published.
They are the earth’s crust; they move very slowly every year. As the tectonic plates slide over each other they cause earthquakes. Earthquakes produce various damaging effects this includes damage to structures of buildings, bridges and other standing formations which then...
Plate tectonics is the theory that landmasses on tectonic plates are in slow constant movement due to convection currents in the mantle. Plate tectonics, or the movements of plates above the lithosphere (the most upper layer of earth's crust) can cause divergent, convergent,and transform boundaries.A boundary the way two tectonic plates collide. is Continental plates are plates that the continents are formed on. Oceanic plates are plates that the ocean covers, and the oceans form on top of these plates. Convergent boundaries and divergent boundaries are ways that these oceanic and continental plates interact with each other. Landforms are formed at boundaries. The landforms formed at boundaries depends on the type of plates that collide, and
Earthquakes belong to the class of most disastrous natural hazards. They result in unexpected and tremendous earth movements. These movements results from dissemination of an enormous amount of intense energy in form of seismic waves which are detected by use of seismograms. The impact of earthquakes leaves behind several landmarks including: destruction of property, extensive disruption of services like sewer and water lines, loss of life, and causes instability in both economic and social components of the affected nation (Webcache 2).