Chapter 3 – The Dynamic Earth Section 1: The Geosphere

1. Chapter 3 – The Dynamic EarthSection 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 • ___________________ • 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 • 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 • ______________________ • 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 ____________ • 15-300 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 • More solid & rigid than asthenosphere due to increased pressure • Can’t flow Lithosphere Asthenosphere Mesosphere Outer Core Inner Core

13. Outer Core • Super-heated molten lava • 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 • ______________ erosion • Removal of most fertile part of soil lowering soil productivity • Creates sand dunes