{"id":368,"date":"2015-09-14T19:02:15","date_gmt":"2015-09-14T19:02:15","guid":{"rendered":"https:\/\/courses.candelalearning.com\/geophysical\/?post_type=chapter&p=368"},"modified":"2017-04-19T21:55:10","modified_gmt":"2017-04-19T21:55:10","slug":"earths-tectonic-plates","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-geophysical\/chapter\/earths-tectonic-plates\/","title":{"raw":"Earth's Tectonic Plates","rendered":"Earth’s Tectonic Plates"},"content":{"raw":"When the concept of seafloor spreading came along, scientists recognized that it was the mechanism to explain how continents could move around Earth\u2019s surface. Scientific data and observation now allows us to merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics.Seafloor and continents move around on Earth\u2019s surface, but what is actually moving? What portion of the Earth makes up the \u201cplates\u201d in plate tectonics? This question was also answered because of technology developed during the Cold War. The plates<\/strong> are made up of the lithosphere.\u00a0During the 1950s and early 1960s, scientists set up seismograph networks to see if enemy nations were testing atomic bombs. These seismographs also recorded all of the earthquakes around the planet. The seismic records could be used to locate an earthquake\u2019s epicenter, the point on Earth\u2019s surface directly above the place where the earthquake occurs.\u00a0Earthquake epicenters outline these tectonic plates. Mid-ocean ridges, trenches, and large faults mark the edges of these plates along with where earthquakes occur.\r\n\r\n\"Map\r\n\r\nThe lithosphere is divided into a dozen major and several minor plates. The plates\u2019 edges can be drawn by connecting the dots that mark earthquakes' epicenters. A single plate can be made of all oceanic lithosphere or all continental lithosphere, but nearly all plates are made of a combination of both.\u00a0Movement of the plates over Earth's surface is termed plate tectonics<\/strong>. Plates move at a rate of a few centimeters a year, about the same rate fingernails grow.\r\n

How Plates Move<\/h2>\r\nIf seafloor spreading drives the plates, what drives seafloor spreading? Picture two convection cells side-by-side in the mantle.\u00a0Hot mantle from the two adjacent cells rises at the ridge axis, creating new ocean crust.\u00a0The top limb of the convection cell moves horizontally away from the ridge crest, as does the new seafloor.\u00a0The outer limbs of the convection cells plunge down into the deeper mantle, dragging oceanic crust as well. This takes place at the deep sea trenches.\u00a0The material sinks to the core and moves horizontally.\u00a0The material heats up and reaches the zone where it rises again.\r\n\r\nhttps:\/\/youtu.be\/p0dWF_3PYh4","rendered":"

When the concept of seafloor spreading came along, scientists recognized that it was the mechanism to explain how continents could move around Earth\u2019s surface. Scientific data and observation now allows us to merge the ideas of continental drift and seafloor spreading into the theory of plate tectonics.Seafloor and continents move around on Earth\u2019s surface, but what is actually moving? What portion of the Earth makes up the \u201cplates\u201d in plate tectonics? This question was also answered because of technology developed during the Cold War. The plates<\/strong> are made up of the lithosphere.\u00a0During the 1950s and early 1960s, scientists set up seismograph networks to see if enemy nations were testing atomic bombs. These seismographs also recorded all of the earthquakes around the planet. The seismic records could be used to locate an earthquake\u2019s epicenter, the point on Earth\u2019s surface directly above the place where the earthquake occurs.\u00a0Earthquake epicenters outline these tectonic plates. Mid-ocean ridges, trenches, and large faults mark the edges of these plates along with where earthquakes occur.<\/p>\n

\"Map<\/p>\n

The lithosphere is divided into a dozen major and several minor plates. The plates\u2019 edges can be drawn by connecting the dots that mark earthquakes’ epicenters. A single plate can be made of all oceanic lithosphere or all continental lithosphere, but nearly all plates are made of a combination of both.\u00a0Movement of the plates over Earth’s surface is termed plate tectonics<\/strong>. Plates move at a rate of a few centimeters a year, about the same rate fingernails grow.<\/p>\n

How Plates Move<\/h2>\n

If seafloor spreading drives the plates, what drives seafloor spreading? Picture two convection cells side-by-side in the mantle.\u00a0Hot mantle from the two adjacent cells rises at the ridge axis, creating new ocean crust.\u00a0The top limb of the convection cell moves horizontally away from the ridge crest, as does the new seafloor.\u00a0The outer limbs of the convection cells plunge down into the deeper mantle, dragging oceanic crust as well. This takes place at the deep sea trenches.\u00a0The material sinks to the core and moves horizontally.\u00a0The material heats up and reaches the zone where it rises again.<\/p>\n