1. SHAPING EARTH’S SURFACE
CHAPTER 4 LESSON 2
SHAPING EARTH’S SURFACE

2. 4.2 INFORMATION

3. EARTHQUAKES
The vibration caused by the rupture and sudden movement of rocks along a break or a crack in Earth’s crust

4. EARTHQUAKES
An earthquake can occur at a fault

5. FAULT
a crack or a fracture in Earth’s crust along which movement occurs.

6. FAULT
Because of the convection currents beneath tectonic plates, forces build up along faults at plate boundaries

7. FAULT RUPTURES
When a fault ruptures, Earth’s crust moves along the fault, causing an earthquake

8. FAULT RUPTURES
Most earthquakes occur at plate boundaries

9. MAGNITUDE
The size of an earthquake

10. MAGNITUDE
Magnitude is determined by how much energy is released during the earthquake.

11. FAULTS
A plate boundary involves more than one fault

12. FAULTS AND SUBDUCTION
Faults are largest where one plate subducts into the mantle, and the strongest and most damaging earthquakes occur there

13. MOVEMENT ALONG FAULTS
The movement of crust along faults can make mountains, valleys, and other landforms

14. TRANSFORM BOUNDARY
Blocks of crust move horizontally past each other at a transform boundary

15. MID-OCEAN RIDGES
Mid-ocean ridges form at divergent boundaries between oceanic plates

16. SUBDUCTION ZONE
At a convergent boundary with a subduction zone, the plate that does not subduct deforms and crumples as the two plates push toward each other.

17. SUBDUCTION ZONE

18. NO SUBDUCTION ZONE
At a convergent boundary without a subduction zone, the edges of both tectonic plates become crumpled and deformed.

19. NO SUBDUCTION ZONE

20. B. VOLCANOES

21. MAGMA
molten rock stored beneath Earth’s surface

22. LAVA
Magma that erupts onto Earth’s surface

23. VOLCANO
vents in Earth’s crust through which molten rock flows

24. CONVERGENT BOUNDARY
Most volcanoes form at convergent plate boundaries

25. CONVERGENT BOUNDARY
At some convergent boundaries, one plate subducts another plate

26. MAGMA RISES
Magma formed from the subducted plate then rises toward the surface and forms volcanoes on the plate that does not subduct

27. LINE OF VOLCANOES
A line of volcanoes forms parallel to the plate boundary directly above the plate that subducted

28. VOLCAOES FORM QUICKLY
Mountains can form over millions of years, but volcanoes can form in hundreds to thousands of years

29. VOLCANIC ERUPTIONS
Volcanoes erupt in two ways

30. LAVA FLOWS
1 - In a lava flow, lava can flow over Earth’s surface before cooling, hardening, and becoming solid rock.

31. ASH ERUPTIONS
2 - Sometimes, volcanoes can erupt explosively, as happened at Mount St. Helens in 1980.

32. ASH ERUPTIONS
Tiny pieces of glass made from solidified lava are called ash and can be blown high into the atmosphere

33. C. OCEAN BASINS

34. LAVA FORMS NEW CRUST
At convergent plate boundaries and divergent plate boundaries, lava hardens and forms new crust

35. LAVA FORMS NEW CRUST
At an oceanic divergent plate boundary, newly formed crust is added to the edges of the plates as new ocean crust

36. MID-OCEAN RIDGES
Long, narrow mountains formed by magma at divergent boundaries

37. MID-OCEAN RIDGES
Three-quarters of all lava erupts at mid-ocean ridges

38. MOUNTAINS FORM
Most mountains form near plate boundaries because folding and crumpling usually occur at the edges of plates

39. MOUNTAIN RANGES
Large mountain ranges form when two continents collide at a convergent plate boundary.

40. HIMALAYAS
The Himalayas are the world’s largest and highest mountain range, and they are still growing

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