The word tectonic derives from the Greek word “tektonikos” which means “pertaining to construction.” Tectonic concerns the formation and structure of the earth’s crust (Oberrecht, n.d.). The plate tectonic theory is the study of the outer rigid layer part of the earth’s crust also known as the lithosphere (JMU, 2000). The plate tectonic theory started about 300 million years ago. The theory suggests that the earth’s surface had one single ocean, which surrounded one super-continent which they called, Pangea. This mass then split and divided into six different plates which now have our six continents (Spilhaus, 1984). By the end of the 1960’s a basic understanding of the earth’s crust was established. They decided that the crust is broken into ten major plates which behave as the rigid body which slides and causes plastically deformations. Most earthquakes are restricted to the crust of the earth, but that doesn’t stop the earthquakes depthness. The depth of the crust does not coincide directly with the depth of the tectonic plate. Continental plates are much deeper than the tectonic plates by at least 70 kilometers (Hough, 2002). Some scientists believe that these plates have a thickness of 50 miles. These plates move relatively to each other a few inches every year due to its hotness and their mobile zone (Pearson Education, 2007).
Many of the earthquakes occur or start where plate boundaries are converging, diverging, or sliding past each other. The most powerful earthquakes are those associated to the plate subduction when one plate thrusts under another (Erickson, 2001). There are the continental plates and the oceanic plates. The continental plates are mainly made up of granite. The oceanic plates are mostly made up of basalt and are heavier which makes them stay at the bottom of the ocean floor (Oberrecht, n.d.). The greatest seismicity corresponds with the deep trenches and volcanic island arcs, which mark the convergence between oceanic and continental plates (Erickson, 2001).
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Many of the earthquakes occur or start where plate boundaries are converging, diverging, or sliding past each other. The most powerful earthquakes are those associated to the plate subduction when one plate thrusts under another (Erickson, 2001). There are the continental plates and the oceanic plates. The continental plates are mainly made up of granite. The oceanic plates are mostly made up of basalt and are heavier which makes them stay at the bottom of the ocean floor (Oberrecht, n.d.). The greatest seismicity corresponds with the deep trenches and volcanic island arcs, which mark the convergence between oceanic and continental plates (Erickson, 2001).
If you would like to learn more about plate tectonics click here