ess3 midterm review

ess3 midterm review - ESS 3 Oceanography Concepts to Review...

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ESS 3 Oceanography Concepts to Review Chapter 3 (skip 3.6-3.7) Earth’s layers - Earth has concentric layers: crust, mantle (largest), liquid outer core, and solid inner core Types and relative velocities of seismic waves - two basic kinds of seismic waves occur: surface waves travel relatively slowly along the surface of Earth, and body waves travel at higher speeds through Earth’s interior. There are two kinds of body waves: P-waves , or primary waves (so called because they travel faster than any other seismic waves and are the first to arrive at a recording station, and S-waves, or secondary waves (so called because they travel more slowly than P-waves and are the second waves to arrive at a station. P-waves, also known as compressional waves, alternately compress and stretch the material they pass through, causing an oscillation in the same direction as they move. P-waves can travel through all three states of matter: solid, liquid, and gas (sound propagates through the air and the oceans as a compressional wave.) S-waves, also known as shear waves, oscillate at right angles to their direction of motion (similar to a plucked string). S-waves propagate only through solids. Arrival times of seismic waves: P and S (body) and surface waves are generated by earthquakes, volcanic eruptions. The wave speeds depend on chemistry, density and physical state (solid, partially molten, molten) Continental Crust vs. Oceanic Crust- Continental crust underlies the continents and is mainly composed of granite rock. Average thickness is about 35 km. Oceanic crust underlies the oceans and is mainly composed of Basalt rock. Average thickness is about 7 km. Continental crust is lighter (less dense) than oceanic crust. Continental crust is granitic. Oceanic crust is basaltic. Oceanic crust subducts under a less dense crust whether it's oceanic or continental. Continental crust does not subduct. Oceanic crust is much younger in geologic age than continental crust. Continental crust is on average thicker than oceanic crust. Lecture Notes : Age of continental crust (2By) >>> oceanic crust (<180-220My), because continents are less dense and always override ocean crust at subduction zones; ocean crust always remelts. Lithosphere - rocks that have pliable behavior will deform, or flow in response to applied force. This has led to the identification of a strong, rigid surface shell called the lithosphere,
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which consists of crust and upper mantle material fused together. It is the lithosphere that comprises the plates of plate tectonics. In oceanic regions, the lithosphere thickens with increasing age of the sea flow. It reaches a maximum thickness of about 100km at an age of 80 million years.
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This note was uploaded on 03/15/2010 for the course ESS 3 taught by Professor Druffel during the Winter '10 term at UC Irvine.

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ess3 midterm review - ESS 3 Oceanography Concepts to Review...

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