The Earth’s Interior

Write down the things that are in yellow Other terms in this PowerPoint are helpful but do not need to be included in your notes.

Plate tectonics- describes movement of the crust (theory) Continental Drift- the continents have drifted from one location to another Continents used to be in one mass called Pangea (250 mill. Years ago)

Earthquakes Seismic Waves – generated waves traveling through the Earth’s interior These waves give us clues to the composition of the Earth

Types of waves P-waves (primary waves) Compress and expand rock Are the fastest First waves to register on seismograph

Types of waves (cont.) S-waves (secondary waves) Vibrate up and down or side to side 2nd waves to register on a seismograph S Waves

Earthquake 1/5/13

IV. Measuring Earthquakes Seismograph Device which measures seismic waves Clicker ?’s 1-9

Movement along a fault boundary Transform-fault boundary – plates are sliding past one another EX. San Andreas fault in California ★ Earthquakes caused by shearing forces

Movement (cont.) B. Divergent Boundary 1. two plates are moving apart  Plate A Plate B  2. Forms rift valleys - large spreading valleys or 3. Creates sea floor spreading- a rift valley on sea floor 4. Caused by tensional forces

Divergent Boundaries

Divergent Boundaries- can observe reverse polarity

Movement (cont.) Convergent Boundaries Leads to subduction- one plate 2 plates move towards each other Plate A   Plate B Leads to subduction- one plate (usually oceanic crust) goes beneath the other (continental crust). Caused by compressional forces

Convergent Boundaries

Convergent Boundaries Ex: Andes Mountains in S. America (Still growing because of subduction) 3. ★Common place to find volcanoes Ex: Cascade Range (Mt. St. Helens & Mt. Rainier)

Rift Valley (divergent) Quiz Time!- word bank (some > 1) Transform Boundary Convergent Boundary Divergent Boundary Continental Crust Oceanic Crust Subduction Rift Valley (divergent) 6. Crust type 7. Crust type 2. 4. 1. 3. 8. 5.

Earth’s internal layers Geologists did research with seismic waves Concluded that the Earth’s interior is layered.

Earth’s internal layers SKETCH THIS!

Earth’s internal layers A. Core- 1. Composed mostly of iron and nickel 2. Inner Core very hot solid Fe & Ni due to high pressure of the Earth

The Core (continued) 3. Outer Core less pressure from the earth liquid Fe & Ni Flow in the outer core generates an electric current that powers the Earth’s magnetic field.

B. The Mantle Rocky layer About 3000 km thick

Mantle (cont.) a. Lower mantle b. Upper mantle – two sections

Upper mantle (cont.) 1. Asthenosphere - behaves in a semi-fluid manner

Upper mantle (cont.) Lithosphere- rigid and brittle Legend Source: http://www.uwsp.edu/geo/faculty/ritter/images/lithosphere/tectonics/earth_structure.jpg Lithosphere- rigid and brittle Legend Lithosphere & Crust Mantle & & & Asthenosphere Outer Core Inner Core

Thickness of layers.

C. The Crust Uppermost portion of the lithosphere Two types of crust a. Oceanic crust – below ocean, dense about 10 km thick

The Crust (cont.) b. Continental crust – below land, less dense about 20-60 km thick

Evidence that supports the theory of Continental Drift 1. Geologic (rock) 2. Biologic (life) 3. Climatological (past weather) 4. Continental Shelves fit together well

Tectonic Plates moving sections of the lithosphere on which continents lie

Major Tectonic Plates Clicker ?’s 1-9 (Continental Drift and Faults)