Earth’s Crust

1. Earth’s Crust in Motion Inside Earth Chapter 2.1 Pages 54-61

2. Stress(ed)? • Stressis the measure of the amount of force applied to a given area.

3. Effect on Rocks • Stress is the force that acts on a rock to change its shape or volume • Adds energy to the rock.

4. Deformation • Deformation:Any change in the shape or volume of Earth’s crust (caused by stress) • Crust deforms from the force of plates colliding • Transform boundaries.

5. Where is the Deformation?

6. Relieving Stress • Over time, stress builds up in the plates • Eventually, the stress is released…

7. Earthquake! Earthquake!

8. Earthquakes • The shaking and trembling that results from the movement of rock beneath Earth’s surface. • Releases MASSIVE amounts of energy • Generates seismic waves

9. Compression • Definition: Squeezing • Effect on Rock: • Makes rock layers thicker and shorter • Associated Fault Type:  • Reverse Fault • Associated Plate Boundary: • Convergent Boundary

10. Tension • Definition: Pulling apart • Effect on Rock: • Stretches making rocks longer and thinner • Associated Fault Type:  • Normal Fault • Associated Plate Boundary: • Divergent Boundary

11. Shear • Definition: Moving in opposite directions • Think of shears or scissors • Effect on Rock: • Stress distorts the shapes of rocks. • Associated Fault Type:  • Strike-Slip • Associated Plate Boundary: • Transform

12. Faults • Afault is a break in the lithosphere • Usually occur along plate boundaries, where the motions of plates compress, pull or shear the crust so much that the crust breaks. • 3 Types of Faults • Strike Slip Fault • Normal Fault • Reverse Fault

13. Hanging Wall Hanging (head) Wall Foot Wall • Above the fault plane.

14. Foot Wall Hanging (head) Wall Foot Wall • Below the fault plane

15. Which Wall’s Which? • Hanging Wall • Lantern • Foot Wall • Path

16. Friction along Faults • How rocks move determines how much friction there is between opposite sides of the fault • Friction:a force that opposes the motion of one surface as it moves across another What about the surfaces causes friction? • It exist because surfaces are not perfectly smooth.

17. Normal Fault • Force: Tension (diverging) • Hanging wall: Moves down (with gravity)

18. Reverse Fault • Force: Compression (converging) • Hanging wall: Moves up (against gravity)

19. Strike-Slip Fault • Force: Shear (transform) • Rocks on both sides of the fault slide past each other

21. Landforms • Topography: determined by its elevation, relief and landform • All landforms have elevation and relief • A landform region is an area where the topography is similar.

22. Elevation • The height above sea-level on Earth’s surface.

23. Relief • The difference between the highest point of elevation and the lowest parts of an area • have high relief • low relief. • Mountains • Plains

24. Plateaus • Have high elevation and relief • Perfectly smooth on top • May be really thick (1,500m), streams or rivers can cut through.

25. Plains • Flat or gently rolling land with low relief and varying elevation. • Depends on location… • Coastal Plains have low elevation at or near sea level along the coast. • Interior Plains are away from the coast, causing varied elevation.

26. Mountains • A landform with high elevation and relief • Mountain Ranges are groups of mountains that are closely related in shape, structure and age.

27. Moraine Lake, CO Rockies

28. Himalayan Mountains, India

29. Mountains formed From Faulting • Normal Faults uplift blocks of rock and the hanging wall drops.

30. Mountains formed From Folding • When continental plates collide, stress can cause rock layers to fold. • Creates bends in the rock layers • Himalayas Mts. • Appalachian Mountains

31. Anticline • A term used to describe folds in rocks • An arching fold in the rock layers or “apex”

32. of the World Archways

33. Syncline • A downward pointing fold or “slump”

34. Anticline/Syncline

35. Anticline/Syncline

36. What to Work On • Read Section 2.1 (pages 54-61) • Answer section review questions (page 61, #1-4)