1. What’s inside the Earth. Is there really another world at the center
What’s inside the Earth? Is there really another world at the center? What is the energy for surface features?

2. Our Dynamic Earth Earth is constantly changing
How do we know it’s dynamic??
Earthquakes (and tsunamis)
Volcanic eruptions
Surface Features:
Mountain Ranges; Mid-Ocean Ridges; Deep-Sea Trenches

3. Topography of the Ocean Floor

4. Topography of the Ocean Floor
Mid-Ocean Ridge

5. Topography of the Ocean Floor
Deep-sea
Trench
Mid-Ocean Ridge

6. Topography of the Ocean Floor
Deep-sea
Trench
Mid-Ocean Ridge
Island
Chain

8. Elevated Continents

9. Submerged Ocean Basins
Elevated Continents
Submerged Ocean Basins

10. Questions: How are the ocean basins formed?
How permanent are these features?
What is the age of the ocean floor?
What’s the age of the continents?
Why are the ocean basins deep and the continents high?

11. The Surface of the Earth
2 levels:
elevated continents
submerged ocean basins
What causes these surface features?
We must know what goes on inside the Earth

12. What’s going on inside the Earth?

13. Early Ideas
Jules Verne

14. “Journey to the Center of the Earth”
Entered in Iceland
Exited in Italy

15. Pellucidar

16. Information about the Earth’s Interior comes from:
Meteorites
Volcanoes
Seismic Waves (“sound images”)
Tremendous pressure enormous heat (from natural radioactivity)

17. Meteor Crater (Arizona)

18. Willamette Meteorite Found 1902, in West Linn Largest in the U.S.A.
Sold and now resides in NYC

19. Volcanoes E.g., Hawaiian “hotspot” Windows into the Earth
Samples 200km down (e.g., diamonds!)

20. Seismic Waves
Sound energy from earthquakes and large explosions

28. Marianas Trench  11 km deep.
DEPTHS
Top of Mantle
10 to 70 km (5 to 30 miles)
Top of Core
2,900 km (2000 miles)
Center of Earth
6,300 km (4,000 miles)
Mt. Everest  9 km high.
Marianas Trench  11 km deep.

29. How do we know what’s inside the Earth?

30. How do we know what’s inside the Earth? Direct Observations:
Exposures on surface up from  50 km (30 miles) depth
Drilling to  15 km (10 miles)
Volcanic Material up from  200 km (120 miles) depth

31. How do we know what’s inside the Earth?

32. How do we know what’s inside the Earth? Indirect Observations:
Magnetic Field
Iron core.
Gravity Field
Densities:
Crust: g/cm3
Mantle: g/cm3
Core: 10.8 g/cm3
Earthquake Seismic Waves
Physical state of crust, mantle, core.

36. Interior of Earth by Strength
LITHOSPHERE
rigid outer shell
crust and upper mantle (~ 50 to 200 km thick)
somewhat brittle, breakable
cold (like butter out of fridge)
ASTHENOSPHERE
warmer, plastic layer under lithosphere
mantle from ~ 150 to 700 km
squishy, plastic
warm (like softened butter)
LOWER MANTLE
Solid, but can flow over time!
~700 to 2900 km
OUTER CORE
liquid
INNER CORE
solid

38. Submerged Ocean Basins
Elevated Continents
Submerged Ocean Basins

39. Swimming Pool

40. Earth’s Mantle

42. Continental Crust
Earth’s Mantle

43. Types of Crust Continental Crust 20 to 70 km (10 to 30 miles) thick.
Composed of highly evolved rocks, like granite (igneous), and metamorphic rocks, squeezed and heated under mountain ranges

44. Continental Crust
Earth’s Mantle

46. Oceanic Crust

47. Types of Crust Continental Crust Oceanic Crust
It is less dense, but thicker than oceanic crust
Oceanic Crust
It is thinner, but more dense than continental crust, so it sits lower than continental crust.
Composed of basalt (volcanic).

50. Thick, Buoyant Continental Crust

51. Thin, Less-Buoyant Oceanic Crust

53. Thick Continental Crust Floats Higher

54. Thick Continental Crust Floats Higher Thin Oceanic Crust Floats Lower

56. Mid-Atlantic Ridge

57. Water Fills in the Low Areas

58. And Hides Features on the Ocean Floor! Water Fills in the Low Areas

59. PLATE BOUNDARIES

60. PLATE TECTONICS Tectonics: From the Greek “tecton” builder “architect”
The study of large features on Earth’s surface and the processes that formed them.

61. PLATE TECTONICS: Large features: continents, mountain ranges
ocean basins
and processes:
earthquakes
volcanic eruptions
These are due to movement of plates of Earth’s outer shell.
All resulting from mantle convection

62. Cracked Egg Shell!