1. Chapter 3 – The Dynamic Earth Section 1: The Geosphere
Describe the composition & structure of the Earth
Describe the Earth’s tectonic plates
Explain the main cause of earthquakes & their effects
Identify the relationship between volcanic eruptions & climate change
Describe how wind & water alter the Earth’s surface

2. The Earth as a System
Earth consists of ________________________, & living things that interact with each other
Divided into 4 parts:
AIR
WATER
LIVING THINGS
ROCK

3. The Earth as a System ___________________ Atmosphere
Solid portion consisting of rock
Extends from center of ____________ to surface of _____________
Atmosphere
Mixture of _________________
Most found in first 30 km above Earth’s surface
________________________
All water on or near surface
Most is _______________
Biosphere
Where _____________ exists
Extends from 9 km above surface to bottom of ocean

4. Discovering Earth’s Interior
_________________used to study interior of Earth
Seismic waves
Travel through Earth’s interior during earthquakes
Altered by type of material they move
Changes in speed & direction measured when passing through different layers
Earthquake
Seismic wave

5. Composition of the Earth
Crust
Divided into three layers based on ______________
Crust
Mantle
Core
layers become progressively _____________ toward the center
Core
Mantle

6. Crust Thin, _____________ layer Solid, ____________
5 to 8 km beneath oceans
20 to 70 km beneath continents
Solid, ____________
Composed of lightweight elements
Makes up less that ____ of Earth’s mass

7. Mantle Layer between crust & core Composed of rock with medium density
Contains ____________ minerals
Makes up _______ of Earth’s mass
Approximately 2900 km thick

8. Core Innermost layer Consists of densest elements
______________________
Super-heated molten lava
Composed of liquid nickel & iron
Sphere of solid nickel & iron
Consists of densest elements
Radius approximately 3400 km
Solid inner core

9. The Structure of the Earth
_____________
Divided into 5 layers based on the ______________ properties
_______________
_____________
_________ Core
__________ Core

10. Lithosphere Composes ___________ & upper part of ____________
km thick (9-185 mi)
Divided into large pieces called ________________ plates
May be oceanic or continental
Slide on fluid portion of mantle
Movement can cause earthquakes

11. Asthenosphere Beneath lithosphere
250 km thick (150 mi)
Solid, plastic-like material of mantle
Made of rock that ______________
Due to temperature & pressure
Allows for movement of tectonic plates

12. Mesophere Lower part of mantle
Lithosphere
Lower part of mantle
More solid & rigid than asthenosphere due to increased pressure
Can’t flow
Asthenosphere
Mesosphere
Outer Core
Inner Core

13. Outer Core Super-heated molten lava Source of Earth’s magnetic field
Composed of ______________ nickel & iron
4000 to 9000 °F
Source of Earth’s magnetic field
Creates protective bubble
Deflects Sun’s solar winds

14. Inner Core _______________ ball Composed of nickel & iron
9000 °F & 45,000,000 psi
Rotates in liquid outer core

15. Plate Tectonics Large, irregularly shaped slabs of rock
Composed of oceanic & continental lithosphere
Continental rocks
Lightweight minerals (quartz, feldspar)
Thicker crust
Oceanic rocks
Heavier, denser basltic rocks
Thinner crust

16. Major & Minor Tectonic Plates
Plates move in different directions and speeds, thus crash together, pull apart or side swipe each other like cars in a demolition derby

17. Plate Boundaries
Most geologic activity occurs where plates _______________or ______________ (called boundaries)
Movement of plates creates 3 types of tectonic boundaries
_______________ – plates collide, move into one another
_______________ – plates move apart
________________ – plates move sideways in relation to one another
Movement of tectonic plates causes
Mountain formation
Earthquakes
Volcanic eruptions

18. Plate Tectonics and Mountain Formation
Plates collide, crust thickens
Rocks break & buckle
Continental plate folds into huge mountain
Oceanic plate forms trench
Examples
Rocky mountains (N. America)
Himalaya mountains (Central Asia

19. Earthquakes
_____________– breaks in Earth’s crust where plates slide past each other
Rocks under stress break off triggering ground vibrations - called earthquakes
Magnitude (Richter Scale)
Measure of energy released
________ – smallest felt
_________ – largest recorded
Increase of 1 whole number = 31.7 times more energy

20. Where Earthquakes Occur
Most occur at or near plate boundaries

21. Earthquake Hazard
Earthquake hazard level determined by past & present seismic activity
Hazards (effects) include
Ground shaking (building damage/settling of ground beneath to different level)
Ground displacement
Flooding (breakage of levies, dams, Tsunamis)
Fire (broken gas & power lines)
Human hazards due to man-made structures
Being crushed, buried or burned or drowning
National Hazards Maps used by cities, counties & local governments to update & create more stringent building codes

22. Volcanoes Mountains built from ______________ (molten rock)
Magma rises to surface from interior
Most common at convergent or divergent plate boundaries
Can occur on land or in oceans
Block between separating faults cracks, drops into asthenosphere forming a rift. Magma seeps upward to fill in crack

23. Volcanoes: The Ring of Fire
Majority of active volcanoes on land located along tectonic plate surrounding the _______________________
North American Plate
Eurasian Plate
South American Plate
Pacific Plate
Australian Plate
Antarctic Plate

24. Local Effects of Volcanic Eruptions
Clouds of hot ash, dust, & gases flow down the slopes of volcanoes searing anything in its path
Obscures ______________, killing plants & animals
Volcanic ash mixes with water producing ________________
Water contamination
Land contamination
_________________ of buildings, burying of crops, & damage to vehicle engines due to falling ash

25. Global Effects of Volcanic Eruptions
Can cause changes in Earth’s ________________
Ash & sulfur-rich gases reach upper atmosphere & ____________________reaching Earth’s surface
Reduction in sunlight reduces average global temperatures

26. _________________
Process resulting in materials of the Earth’s surface being loosened, dissolved or worn away & transported from one place to another by natural agents such as wind, water, ice or gravity
______________ erosion
Rivers carve deep canyons or gorges into bedrock
Depositing of dust, pebbles, rocks forms new land areas
Oceans erode coastlines
Removal of most fertile part of soil lowering soil productivity
Creates sand dunes