2. Exploring Geography
CHAPTER 1

3. Section 2 Changes Within the Earth Objectives:
Describe both the internal and external structures of the Earth.
Explain how forces inside the earth create and change landforms.
Summarize the main ideas of plate tectonic theory.

4. - the study of the earth’s physical structure and history.
Geology
- the study of the earth’s physical structure and history.

5. Vocabulary BEFORE AFTER Key Terms: Core Mantle Crust Continents Relief
Lava
Fold
Faults
Plate Tectonics
Continental Drift Theory
Ring of Fire
BEFORE
AFTER

6. Changes Within the Earth
The Earth’s Structure
Internal Forces
Geologic History

8. Plumbing System of a Volcano
Fig. 5.1

10. Ejecta ash volcanic bombs volcanic tuff volcanic breccias
pyroclastic flow (look out!)

11. Escaping a Pyroclastic Flow at Mount Unzen, Japan, 1991

12. Shield Volcano
Fig. 5.10

15. Cinder Cone
Fig. 5.12

18. Composite Volcano
Fig. 5.14

19. Before May, 1980
Emil Muench/Photo Researchers

23. After May, 1980
David Weintraub/Photo Researchers

24. fissure eruption

25. 1971 Fissure Eruption, Kilauea, Hawaii

26. Plate Tectonics:
the unifying theory

27. Plate Tectonics: The Unifying Theory
Peter W. Sloss, NOAA-NESDIS-NGDC

28. “Fit” of the Continents
Fig. 20.1

29. Pangaea 250 Million Years Ago
Fig.21.1

30. Relative Motion of the Plates

31. Relative Velocity and Direction of Plate Movement
Fig
Data from C. Demets, R.G> Gordon, D.F. Argus, and S. Sten, Model Nuvel-1, 1990

32. Age of Seafloor Crust
Fig
R. Dietmar Muller, 1997

33. Types of plate boundaries
• divergent: mid-ocean ridges
• convergent: collision zones
volcanic arcs
• strike-slip: San Andreas fault

34. Divergent boundaries Two types: Examples:
Continent-Continent East African
Rift
Ocean–Ocean Mid-Atlantic
Ridge

35. Continental-Continental Divergent plate boundary
East African Rift Valley

37. Inception of Rifting Within a Continent
Fig. 20.4b

38. Cooling and subsidence of rifted margin allows sediments to be deposited
Fig b

39. Gulf of ‘Aqaba Gulf of Suez
Nile Delta
Gulf of
‘Aqaba
Gulf of
Suez
Red Sea
Fig. 20.5a
Earth Satellite Corp.

40. Oceanic-Oceanic Divergent Plate Boundary
Mid-Atlantic Ridge

41. Rifting and Seafloor Spreading Along the Mid-Atlantic Ridge
Fig. 20.4a
Peter W. Sloss, NOAA-NESDIS-NGDC

42. Rifting and Seafloor Spreading
Fig. 20.4a

44. Convergent boundaries
Three types: Examples:
ocean–ocean Japan
ocean–continent Andes
continent–continent Himalaya

45. Oceanic-Oceanic Convergent Plate Boundary
Japan

46. Ocean–Ocean Subduction Zone
Fig. 20.6b

48. Parts of an Ocean–Ocean Convergent Plate Boundary
Fig

49. Oceanic-Continental Convergent Plate Boundary
Andes Mountains

50. Ocean-Continent Subduction Zone
Fig. 20.6a

51. Parts of an Ocean–Continent Convergent Plate Boundary
Fig

53. Continental-Continental Convergent Plate Boundary
India & Asia

54. Continent-Continent Collision
Fig. 20.6c

55. Continent– Continent Collision
Fig b

56. Continent–Continent Convergent Boundary
Fig. 20.d

59. Indian plate subducts beneath Eurasian plate
60 million years ago
Fig.21.6a

60. Indian subcontinent collides with Tibet
40–60 million years ago
Fig.21.6b

61. Main boundary fault develops
10–20 million years ago
Fig.21.6d

62. Transform Plate Boundary
San Andreas Fault

64. The Gulf of California Formed by Rifting of Baja California from Mainland Mexico
Fig. 20.5b
Worldsat International/Photo Researchers

65. Examples of Plate Boundaries
O-C
convergent
O-O
divergent
C-C
divergent
O-O
divergent
O-O
convergent
O-O
divergent
O-C
convergent
Fig. 20.8a,b