1. Introduction to Earth Structure
A Big Picture Overview

2. To sustain such topography the earth must be dynamic

3. Earth’s primary
Layered structure

4. What is the “shallow” structure?
Shallow = ~ 200 km
Note the names of the layers and thicknesses.
Not labelled: Inner core begins at
~ 5,150 km depth

5. CRUST and UPPER MANTLE

6. Note: does not show full lithospheric depth!

7. Bathymetry (topography of the ocean floor)

8. 8000 m
- 10,400 m
Reference (“0”)
Features of the topography?

9. “Hypsometric Curve”

10. Typical Numbers for “crustal thickness”
Continental: Average ~ 35 km
Continental: Range: 20 – 75 km
Oceanic: Average ~ 7 km
Oceanic: Range ~ 5 – 10 km
Lithosphere: (fill in yourself!)
Asthenosphere: (fill in yourself!)

11. Cross section of the earth

12. EARTH’S DENSITY AS A FUNCTION OF DEPTH
APPROXIMATE COMPOSITION OF MAJOR LAYERS

13. DENSITY vs
DEPTH

14. Composition in the
major layers of the
Earth

15. What is the earth made of?

16. What is the temperature inside the earth?
“geothermal gradient”

17. All this suggests the earth has a roughly “layered structure”
What is the layered structure?
How was it discovered?
All this suggests the earth has a roughly “layered structure”

20. Cross section of the earth

32. Earth’s magnetic field is not the result of a “bar magnet” in the interior.

33. Earth’s Magnetic Field Reversal (Simulation)