earthinterior - Physical Geology 101 23 Earth's Interior(p...

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1 23. Earth's Interior (p. 326-345) Layers in the Earth We learned earlier in this course that the interior of the Earth consists of several layers, with each layer having different properties to the others. The thin brittle layer around the outside is called the ______________. Below this is the _____________, which extends half-way to the center of the Earth. The upper part of the mantle is brittle, like the crust. Because of their similar behavioral characteristics, they are typically grouped together, referred to as the ______________. Below the lower portion of the mantle is the _________________, which is liquid. The center of the Earth is made up of the _______________, which is solid. So how do we know about these different layers and their properties? One of the first lines of evidence that the interior of the Earth is different to the rocks at the surface was through calculations of the gravitational attraction between the Earth and the Moon, which can be used to estimate the relative densities of the two bodies. It was calculated that the Earth must have an average density of about _______ g/cm 3 . What is the typical density of rocks near the Earth s surface? ____________ g/cm 3 . What do these differences in density tell us about the density of Earth s interior? ___________________________________________________ But it doesn't tell us how we know there are distinct layers of different density. That's because we only managed to discover this by analyzing the behavior of seismic waves generated by _____________________. The study of seismic waves to discover information about the interior of the Earth is a branch of geology called _____________________. Seismic Waves and the Earth's Interior Seismic waves radiate out in all directions away from the focus of an earthquake. We can represent the motion of these waves away from the focus using arrows that we call ___________________. They show the directions the waves are moving. Each of the different types of seismic waves moves at a different speed. This speed is controlled by the properties of the rock that the wave is moving through. Waves move faster through rocks that are ________________ and _______________.
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This note was uploaded on 01/13/2012 for the course GEOL 101 taught by Professor Williams,t during the Fall '08 term at Idaho.

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earthinterior - Physical Geology 101 23 Earth's Interior(p...

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