1. Changing Earth’s Surface
Weathering and Erosion

2. Changes to Earth’s Surface
Earth’s crust is constantly in a process of change
Weathering
Erosion
Deposition

3. Weathering
The process by which rocks are broken down into small pieces called sediment
Caused by
Wind
Water
Glaciers
Meteorites

4. Erosion
Occurs when weathered material is carried away by wind or water
Responsible for some of our most impressive natural monuments
Example—The Grand Canyon

5. Deposition Occurs when sediment is dropped off at a new location
Wind or water slows down or comes to a stop
Example—River Delta

6. Changing Earth’s Surface
Volcanoes

7. Plate Tectonics
Theory that the lithosphere is divided into plates that are always moving
Pangaea
Supercontinent that once existed over 350 million years ago
Evidence: Puzzle piece fit of the continents, fossil and soil matches on different continents
Responsible for the formation of volcanoes and earthquakes

9. Volcanoes Form when magma rises to Earth’s surface Pyroclastic Flow
Ashes, Gases, and Magma that ooze or explode from volcanoes
Can form at divergent boundaries or subduction zones

10. Divergent Volcanoes Plates above the asthenosphere separate
Magma rises up
As lava cools, new crust is formed
May be oozing or explosive

11. Divergent Volcano

12. Subduction Volcanoes
Formed when a denser ocean plate sinks under a lighter plate (either ocean or land)
Magma comes to the surface

13. Shield Volcano Broad and flat volcano
Resemble a shield laying on its side
Built up slowly over thousands of years, most often in layers of hardened lava
Mostly ooze lava from vents
Example—Mauna Loa, Hawaii

14. Composite Volcano
Formed of alternating layers of ashes and hardened lava
May be dormant for many years before exploding rapidly or may ooze for thousands of years
Example—Crater Lake, OR

15. Cinder Cone Formed from blobs of congealed lava in a simple cone shape
Capable of violent explosions
Bowl-shaped crater at the summit
Example—Paricutin, Mexico

16. Changing Earth’s Surface
Earthquakes

17. World Earthquake Map

18. Earthquakes
Energy released from the snap and slide of Earth’s crust at a fault line
Fault
2 or more plates slide past one another
Focus
Point inside Earth where an Earthquake begins
Epicenter
Point on Earth’s surface where Earthquake waves begin

20. 3 Types of Seismic Waves Primary (P) Waves Secondary (S) Waves
Fastest and Smallest Waves
Secondary (S) Waves
Medium Waves
Surface (R) Waves
Slowest and Most Dangerous Waves

21. Earthquake Waves Measured with a seismograph
Scaled using the Richter Scale
Scale of 1-10
1 = least amount of damage
10 = greatest amount of damage