e3.pdf - find more resources at oneclass.com Midterm Prep Wednesday October 18 2017 11:14 AM \u25a0 10)Cascadia subduction zone off the west coast of

e3.pdf - find more resources at oneclass.com Midterm Prep...

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The Cascadia subduction zone (also referred to as the Cascadia fault ) is a convergent plate boundary that stretches from northern Vancouver Island to northern California . It is a very long, sloping subduction zone that separates the Explorer , Juan de Fuca , and Gorda plates, on the one hand, and the North American Plate , on the other. The denser oceanic plate is subducting beneath the less dense continental plate offshore of British Columbia , Washington , Oregon , and northern California . The North American Plate is moving in a southwest direction, overriding the oceanic plate. The Cascadia subduction zone is where the two plates meet. Tectonic processes active in the Cascadia subduction zone region include accretion, subduction, deep earthquakes, and active volcanism of the Cascades . This volcanism has included such notable eruptions as Mount Mazama ( Crater Lake ) about 7,500 years ago, Mount Meager about 2,350 years ago, and Mount St. Helens in 1980. [1] Major cities affected by a disturbance in this subduction zone include Vancouver and Victoria , British Columbia; Seattle , Washington; and Portland , Oregon. § 10)Cascadia subduction zone off the west coast of Canada 1) Major spreading ridges – especially the mid-Atlantic ridge and the East Pacific rise A mid-ocean ridge is an underwater mountain system formed by plate tectonics . Itconsists of various mountainslinked in chains, typically having a valley knownas a rift runningalong its spine. This type of oceanic mountain ridge is characteristic of whatis knownas an oceanic spreading center , whichis responsible for seafloor spreading . The productionof new seafloor results from mantle upwelling in response to plate spreading;this isentropic upwelling solid mantle material eventually exceeds the solidus and melts. The buoyantmelt rises as magma at a linear weaknessin the oceanic crust , and emerges as lava , creating new crust uponcooling. A mid-ocean ridge demarcates the boundarybetween two tectonic plates , and consequentlyis termed a divergent plate boundary . Midterm Prep: Wednesday, October 18, 2017 11:14 AM find more resources at oneclass.com find more resources at oneclass.com
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boundary . he East Pacific Rise is a mid-oceanic ridge , a divergent tectonic plate boundarylocated along the floor of the Pacific Ocean . It separates the Pacific Plate to the west from(northto south) the North American Plate , the Rivera Plate , the Cocos Plate , the Nazca Plate , andthe Antarctic Plate . It runsfrom southfromthe Gulf of California in the Salton Sea basin in southern California to a pointnear 55°S, 130°W where it joins the Pacific-Antarctic Ridge trending west-southwest towards Antarctica near New Zealand (thoughin some usesthe PARis regarded as the southernsection of the EPR).Much of the rise lies about 3200 km(2000 mi) off theSouthAmerican coast andrises about 1,800–2,700m(6,000–9,000 ft) abovethesurroundingseafloor. The Mid-Atlantic Ridge (MAR) is a mid-ocean ridge , a divergent tectonic plate or constructive plate boundarylocated along the floor of the Atlantic Ocean , and part of the longest mountain range in the world . In the North
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