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The Lithosphere. The Crust Thin, rocky outer layer Either oceanic or continental – Oceanic is 7-km thick – Continental is 8-75 km thick.

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Presentation on theme: "The Lithosphere. The Crust Thin, rocky outer layer Either oceanic or continental – Oceanic is 7-km thick – Continental is 8-75 km thick."— Presentation transcript:

1 The Lithosphere

2

3 The Crust Thin, rocky outer layer Either oceanic or continental – Oceanic is 7-km thick – Continental is 8-75 km thick

4 The Mantle 82% of Earth’s volume 2890-km thick Solid rock at the top Liquid rock at the bottom

5 The Core Composed of an iron-nickel alloy Extreme pressure found at the center

6 Outer Core – Liquid layer – 2260-km thick – Metallic iron flow creates Earth’s magnetic field Inner Core – Solid layer – Radius of 1220-km – High temperature – High pressure – Mostly nickel

7 Layers based on Physical Properties Lithosphere Asthenosphere

8 Layers based on Physical Properties Lithosphere – Crust and Upper most mantle – Cool, rigid shell – 100-km thick Asthenosphere – Below the Lithosphere – Soft, comparatively weak layer – Rocks close to melting

9 Types of Rocks?

10 Types of Rocks Igneous Rock – Forms when lava or magma cools Sedimentary Rock – When existing rocks are broken down into pieces then compacted and cemented together Metamorphic Rocks – When existing rocks are changed by heat and pressure

11 What is the ROCK CYCLE?

12 The Rock Cycle

13 What is Continental Drift?

14 Proposed by Alfred Wegener Stated that the continents had once been joined to form a single supercontinent Supercontinent was called Pangaea

15 What did the Theory Say? Occurred 500 million years ago Pangaea broke apart 200 million years ago Continents “Drifted” (moved) to present positions Continents “broke” through the oceans North America and Africa split 135 million years ago

16 Evidence of Continental Drift

17 Shorelines look like they fit together Same fossil organisms found on different landmasses Several mountain belts end at one coastline, only to reappear on a land mass across the ocean Ancient Climates relate

18 The Theory of Plate Tectonics

19 Plate Boundary Activities?

20 Plate Boundary Activities Earthquakes Volcanoes Mountain Building Sea Floor Spreading

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22 Types of Plate Boundaries …………………………………………..

23 Types of Plate Boundaries Divergent Boundary Convergent Boundary Transform Fault Boundary

24 Plate Boundary? When two plates move apart Also called spreading centers New crust is created (mainly seafloor) – Known as sea floor spreading Causes Ocean Ridges and Rift Valleys (on continents)

25 Plate Boundary? Two plates move toward each other 3 versions – Oceanic-Continental – Continental-Continental – Oceanic-Oceanic

26 Oceanic-Continental Convergent Boundary Oceanic plate goes beneath the continental plate Causes:

27 Oceanic-Continental Convergent Boundary Oceanic plate goes beneath the continental plate Causes – Subduction zones – Trenches – Continental Volcanic arcs (ex: The Andes)

28 Continental-Continental Convergent Boundary Two continental plates collide Causes:

29 Continental-Continental Convergent Boundary Two continental plates collide Causes Mountains to form – Ex: Appalachians, Himalayas, Alps

30 Oceanic-Oceanic Convergent Boundary One oceanic plate goes beneath another oceanic plate Causes:

31 Oceanic-Oceanic Convergent Boundary One oceanic plate goes beneath another oceanic plate Causes Volcanic Island Arc – Ex: Aleutian Islands

32 Transform Fault Plate Boundary Two plates grind past each other No production or destruction of lithosphere Causes:

33 Transform Fault Plate Boundary Two plates grind past each other No production or destruction of lithosphere Causes Earthquakes – Ex: San Francisco

34 What Causes Plate Movement?

35 Convective Flow – The circulation of magma that pushes & pulls plates Driving Force is heat

36 What is a Fault?

37 Fracture in Earth where movement has taken place Most times near Plate Boundaries

38 Parts of a Fault Hanging Wall Foot Wall

39 Parts of a Fault Hanging Wall – Rock above the fault line Foot Wall – Rock below the fault line

40 What are the types of Faults? Normal Reverse Thrust Strike-Slip

41 Types of Faults ……………….. …………………

42 …………

43 Types of Faults Normal Fault – Occurs when the hanging wall block moves down relative to the footwall block Reverse Fault – Occurs when the hanging wall block moves up relative to the footwall block

44 Thrust Fault – A reverse fault with dips of less than 45 degrees Strike-Slip Fault – Movement is horizontal; “side-by-side motion”

45 Evidence of Plate Tectonics

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48 1.Paleomagnetism – Most persuasive evidence – Ancient magnetism found in the rocks – Records show a shift in the poles

49 2.Earthquake Patterns – Connection between deep-focus earthquakes and ocean trenches 3.Ocean Drilling – Young rocks are near ocean ridge crest – Oldest rocks are near the continental margins

50 4.Hot Spots – A concentration of heat in the mantle capable of producing magma, which rises to Earth’s surface – Supports that the plates move over Earth’s surface – Ex: Hawaiian Island Chain

51 Volcanoes and Earthquakes

52 Magma verse Lava?

53 Magma verse Lava Magma – Molten rock under the surface of Earth Lava – Molten rock on the surface of Earth

54 Factors Affecting Eruption?

55 Factors Affecting Eruption Magma Composition Magma Temperature Amount of Dissolved Gases

56 Viscosity of Magma

57 Substance’s resistance to flow Hotter the magma, more fluid and less viscous Directly related to its silica content – More silica, greater its viscosity (slower movement)

58 Dissolved Gases Consist of : More gases, the more _________ the eruption

59 Dissolved Gases Consists mostly of water vapor and carbon dioxide More gases, the more violent the eruption

60 Pyroclastic Material

61 – Fragments ejected during eruptions – From very fine to several tons – Ex: Volcanic Ash Cinders (lapilli) Volcanic Bombs

62 Other Eruption Results Pyroclastic Flow Lahar

63 Other Eruption Results Pyroclastic Flow – Consist of hot gases, glowing ash, and large rock fragments – Races down the steep slope Lahar – Mudflow that occurs when volcanic debris becomes saturated with water and rapidly moves down steep volcanic slopes

64 Ring of Fire

65 Area around the pacific ocean with extreme volcanic activity This shows the Pacific Plate Boarder

66 Parts of an Earthquake Focus Epicenter Fault

67 Parts of an Earthquake Focus – Point within Earth where the earthquake starts Epicenter – Location on the surface directly above the focus Fault – Associated with earthquakes activity where movement has occurred

68 Causes of Earthquakes Elastic Rebound Hypothesis

69 Causes of Earthquakes Elastic Rebound Hypothesis – Release of built-up energy – Most earthquakes are produced by the rapid release of elastic energy stored in rock that has been subjected to great forces – When the strength of the rock exceeded, it suddenly breaks, causing the vibrations of an earthquake

70 Earthquake Waves Two Main Types

71 Earthquake Waves Two Main Types – Surface Waves – Body Waves P-waves S-waves

72 Surface Waves

73 Seismic waves that travel along Earth’s outer layer Moves up & down and side to side Most destructive Last to arrive at the seismograph

74 Body Waves P-Waves (primary waves)

75 S-Waves (secondary waves)

76 Body Waves P-Waves (primary waves) – They push (compress) and pull (expand) rocks in the direction the wave travels – Can travel through solids, liquids and gases – Fastest waves – First to the seismograph

77 S-Waves (secondary waves) – Shakes particles at right angles to their travel – Can only travel through solids – 2 nd to the seismograph

78 Locating Earthquakes The difference in velocity of a P- Wave & S-Wave provides a way to locate the epicenter – Use a travel-time curve graph – Needs at least _______? seismograph station data

79 Locating Earthquakes The difference in velocity of a P- Wave & S-Wave provides a way to locate the epicenter – Use a travel-time curve graph – Needs at least three seismograph station data

80 The Richter Scale

81 Measures magnitude Based on the amplitude of the largest seismic wave A TEN-FOLD system Largest earthquake record= 9.6 (CHILE)

82 Moment Magnitude Scale

83 Mercalli Intensity Scale

84 Moment Magnitude Scale More precise Amount of displacement that occurs along a fault zone Most widely used – Estimates energy released by earthquakes

85 Mercalli Intensity Scale How much damage occurs Depends on: – Strength – Distance from the epicenter – Nature of the surface material – Building design

86 Earthquake Hazards

87 Seismic Vibrations – Damage to building depends on several factors Intensity of vibration Duration of vibration What type of material built on Design of the structure

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89 Liquefaction – Stable soil turns into a liquid that is not able to support building or other structures

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91 Tsunami – Large ocean wave created by an earthquake

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93 Landslides – Greatest damage to structures – Sinking of the ground triggered by the vibration Fires – Caused by ruptured gas lines


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