Geologist & Earth’s Interior Date: Entry: Geologist & Earth’s Interior

1. Geology: study of Earth and processes that shape Earth. A. Geologist = scientist that study Earth

a. building up mountains and landmasses i. earthquakes ii. volcanoes I. Constructive forces a. building up mountains and landmasses i. earthquakes ii. volcanoes

a. slowly wear away i. erosion II. Destructive forces a. slowly wear away i. erosion

2. Basic Structure of Earth A. crust The outermost layer Thinnest - oceanic crust Thickest - continental crust Lower Crust is also called the lithosphere

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III. Oceanic crust is basalt and is more dense than continental crust of granite

B. mantle is the largest layer Top portion is called the asthenosphere Density increases with depth due to increasing pressure Hot softened rock mostly iron and magnesium

C. outer core is beneath the mantle It is a slow flowing liquid of iron and nickel Density, temperature and pressure increase Spinning of liquid creates magnetic field

D. inner core Earth’s center is solid, made mostly of iron and nickel Heaviest material and most dense layer Hottest layer

3. A review wave movement Density of material = speed change More dense faster, less dense slower Density change = direction change Greater the difference in density the greater the direction changes

4. Mapping Earth’s Internal Structure (How we know) I. seismic waves change as they travel through materials with different densities II. densities increase with depth as pressures increase so waves travel differently

III. Use seismic waves used to map Earth’s internal structure

5. Layer Boundaries A. Seismic waves travel faster through a more dense solid region, Slower in the less dense liquid region

Solid = faster Liquid = slower More dense=faster Less dense=slower

C. Seismic waves speed up when they pass from the crust into the mantle I. Mantle is more dense

D. Outer core is liquid because secondary seismic waves do not go through liquid E. Primary waves slow down at liquid outer core, speed up at solid inner core

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click here to watch video of Earth's layers