Folding, Faulting,and Earthquakes      Chapter 9
Diastrophism• Folding and faulting causing deformation  of Earth’s crust on a large scale is called  diastrophism
Compression, Tension, and         Shearing stresses• Compression is force exerted inward  • Tension is a pulling apart ...
Crustal Fold Structures
Crustal Fold Structures• monocline—a one-sided slope
Crustal Fold Structures• monocline—a one-sided slope• syncline—a downfold that creates a U-shape
Crustal Fold Structures• monocline—a one-sided slope• syncline—a downfold that creates a U-shape• anticline—an upfold that...
Crustal Fold Structures•   monocline—a one-sided slope•   syncline—a downfold that creates a U-shape•   anticline—an upfol...
Crustal Fold Structures• monocline—a one-sided slope• syncline—a downfold that creates a U-shape• anticline—an upfold that...
FaultsEventually, even the plastic crust will break…
Normal Fault(tension stress)
Fault Block Mountains The Sierra Nevadas
Reverse Fault(compression stress)
Strike-slip/Transform/Transcurrent Fault              (shear stress)
The San Andreas runs rightthrough the town of Hollister, CA…
Common Structures Associated   with Transform Faults
Thrust Fault(compression stress—low-angle)
Earthquakes         or Hypocenter
Earthquake Measurement
Earthquake Measurement   Seismic waves—Energy waves propagated during an    earthquake
Earthquake Measurement   Seismic waves—Energy waves propagated during an    earthquake   Seismograph—Recording device fo...
Earthquake Measurement   Seismic waves—Energy waves propagated during an    earthquake   Seismograph—Recording device fo...
Quantitative vs. Qualitative Seismic Measurements
Quantitative vs. Qualitative Seismic Measurements
Quantitative vs. Qualitative      Seismic Measurements• Quantitative—Objective, fact-based  measurement; mathematical
Quantitative vs. Qualitative      Seismic Measurements• Quantitative—Objective, fact-based  measurement; mathematical
Quantitative vs. Qualitative      Seismic Measurements• Quantitative—Objective, fact-based  measurement; mathematical• Qua...
Measuring Seismic Waves
Measuring Seismic Waves• Richter Scale—A numerical expression of the  amount of energy released during an earthquake  even...
Measuring Seismic Waves• Richter Scale—A numerical expression of the  amount of energy released during an earthquake  even...
Measuring Seismic Waves• Richter Scale—A numerical expression of the  amount of energy released during an earthquake  even...
Measuring Seismic Waves• Richter Scale—A numerical expression of the  amount of energy released during an earthquake  even...
Measuring Seismic Waves• Richter Scale—A numerical expression of the  amount of energy released during an earthquake  even...
Measuring Seismic Waves
Measuring Seismic Waves• Moment Magnitude Scale
Measuring Seismic Waves• Moment Magnitude Scale  – More accurate at higher magnitudes
Measuring Seismic Waves• Moment Magnitude Scale  – More accurate at higher magnitudes  – Equations used to compare larger ...
Measuring Seismic Waves• Moment Magnitude Scale  – More accurate at higher magnitudes  – Equations used to compare larger ...
Measuring Seismic Waves• Moment Magnitude Scale  – More accurate at higher magnitudes  – Equations used to compare larger ...
Measuring Seismic Waves• Moment Magnitude Scale  – More accurate at higher magnitudes  – Equations used to compare larger ...
Measuring Seismic Waves• Moment Magnitude Scale  – More accurate at higher magnitudes  – Equations used to compare larger ...
Measuring Seismic Waves
Measuring Seismic Waves• Mercalli Scale
Measuring Seismic Waves• Mercalli Scale  – Measures an earthquake’s intensity    (Qualitative)
Measuring Seismic Waves• Mercalli Scale  – Measures an earthquake’s intensity    (Qualitative)  – Based on what people feel
Measuring Seismic Waves• Mercalli Scale  – Measures an earthquake’s intensity    (Qualitative)  – Based on what people fee...
Measuring Seismic Waves• Mercalli Scale  – Measures an earthquake’s intensity    (Qualitative)  – Based on what people fee...
Measuring Seismic Waves• Mercalli Scale  – Measures an earthquake’s intensity    (Qualitative)  – Based on what people fee...
Measuring Seismic Waves• Mercalli Scale  – Measures an earthquake’s intensity    (Qualitative)  – Based on what people fee...
Measuring Seismic Waves• Mercalli Scale  – Measures an earthquake’s intensity    (Qualitative)  – Based on what people fee...
Loma Prieta Quake, 1989
Loma Prieta Quake
Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)
Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)
Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)• Severely shook the San Fr...
Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)• Severely shook the San Fr...
Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)• Severely shook the San Fr...
Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)• Severely shook the San Fr...
Loma Prieta Quake, 1989
Seismic Waves
Seismic Waves• Body waves
Seismic Waves• Body waves  – Travel deep beneath the surface
Seismic Waves• Body waves  – Travel deep beneath the surface    • P-waves
Seismic Waves• Body waves  – Travel deep beneath the surface    • P-waves    • S-waves
Seismic Waves• Body waves  – Travel deep beneath the surface    • P-waves    • S-waves• Surface waves
Seismic Waves• Body waves  – Travel deep beneath the surface    • P-waves    • S-waves• Surface waves  – Travel at or near...
Seismic Waves• Body waves  – Travel deep beneath the surface    • P-waves    • S-waves• Surface waves  – Travel at or near...
Seismic Waves• Body waves  – Travel deep beneath the surface    • P-waves    • S-waves• Surface waves  – Travel at or near...
Seismic Waves   P-waves: Pressure or    Primary waves       Travel fastest         First to arrive       Travel throug...
Seismic Waves   P-waves: Pressure or    Primary waves       Travel fastest         First to arrive       Travel throug...
Seismic Waves   S-waves: Secondary or    Shear waves       Slower than P-waves           Second to arrive       Travel...
Seismic Waves   S-waves: Secondary or    Shear waves       Slower than P-waves           Second to arrive       Travel...
Seismic Waves   S-waves: Secondary or    Shear waves       Slower than P-waves           Second to arrive       Travel...
Seismic Waves• Love waves  – Push rocks from side to side as the motion of the    wave follows a horizontal ellipse which ...
Seismic Waves• Rayleigh waves produce an up and down  motion created by a forward roll, much like that  of an oscillating ...
Both L-waves and R-waves:
Both L-waves and R-waves:• Can travel only through solids
Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event
Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exp...
Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exp...
Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exp...
Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exp...
Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exp...
Earthquakes and theRelationship to Plate Tectonics
Pinpointing an Earthquake
Pinpointing an Earthquake
Earthquake Hazard Map
Earthquake Hazards
Earthquake Hazards• Falling debris and rock material
Earthquake Hazards• Falling debris and rock material• Crumbling buildings
Earthquake Hazards• Falling debris and rock material• Crumbling buildings• Ground cracks
Earthquake Hazards•   Falling debris and rock material•   Crumbling buildings•   Ground cracks•   Broken bridges
Earthquake Hazards•   Falling debris and rock material•   Crumbling buildings•   Ground cracks•   Broken bridges•   Landsl...
Earthquake Hazards•   Falling debris and rock material•   Crumbling buildings•   Ground cracks•   Broken bridges•   Landsl...
Earthquake Hazards•   Falling debris and rock material•   Crumbling buildings•   Ground cracks•   Broken bridges•   Landsl...
Liquefaction
Liquefaction• Liquefaction
Liquefaction• Liquefaction  – (from Latin liquefacere meaning “to liquefy”)
Liquefaction• Liquefaction  – (from Latin liquefacere meaning “to liquefy”)  – Settling of solid material and rising of wa...
Liquefaction• Liquefaction  – (from Latin liquefacere meaning “to liquefy”)  – Settling of solid material and rising of wa...
Liquefaction• Liquefaction  – (from Latin liquefacere meaning “to liquefy”)  – Settling of solid material and rising of wa...
Liquefaction• Liquefaction  – (from Latin liquefacere meaning “to liquefy”)  – Settling of solid material and rising of wa...
Liquefaction• Liquefaction  – (from Latin liquefacere meaning “to liquefy”)  – Settling of solid material and rising of wa...
Liquefaction• Liquefaction  – (from Latin liquefacere meaning “to liquefy”)  – Settling of solid material and rising of wa...
Liquefaction
Liquefaction under Kawagishi-cho apartment       buildings, Niigata quake, 1964
San Francisco: Original Shoreline     Liquefaction Potential?
The Pacific Ring of Fire
The Pacific Ring of Fire
Oceanic-Oceanic Subduction
Oceanic-Oceanic SubductionProduces:  – Big earthquakes and volcanic islands  – A deep ocean trench
What Does a Tidal Wave      Look Like?
What Does a Tidal Wave      Look Like?    Truro, Nova Scotia, Canada
You meant a Tsunami, right?
You meant a Tsunami, right?
You meant a Tsunami, right?
Oceanic-Oceanic SubductionProduces:  – Big earthquakes and volcanic islands, called    “island arcs”  – A deep ocean trenc...
Tsunamis
Tsunamis• Waves caused by undersea volcanic or tectonic  events (earthquakes)
Tsunamis• Waves caused by undersea volcanic or tectonic  events (earthquakes)• Unnoticed by observers on the open ocean
Tsunamis• Waves caused by undersea volcanic or tectonic  events (earthquakes)• Unnoticed by observers on the open ocean• C...
Tsunamis• Waves caused by undersea volcanic or tectonic  events (earthquakes)• Unnoticed by observers on the open ocean• C...
Tsunamis• Waves caused by undersea volcanic or tectonic  events (earthquakes)• Unnoticed by observers on the open ocean• C...
Sumatra Quake, Dec. 26, 2004http://www.nytimes.com/packages/khtml/2004/12/26/   international/20041227_QUAKE_FEATURE.html
GEOG 100--Lecture 14--Earthquakes
GEOG 100--Lecture 14--Earthquakes
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GEOG 100--Lecture 14--Earthquakes

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  • GEOG 100--Lecture 14--Earthquakes

    1. 1. Folding, Faulting,and Earthquakes Chapter 9
    2. 2. Diastrophism• Folding and faulting causing deformation of Earth’s crust on a large scale is called diastrophism
    3. 3. Compression, Tension, and Shearing stresses• Compression is force exerted inward  • Tension is a pulling apart  • Shearing occurs when force is exerted in opposite directions, but parallel to one another 
    4. 4. Crustal Fold Structures
    5. 5. Crustal Fold Structures• monocline—a one-sided slope
    6. 6. Crustal Fold Structures• monocline—a one-sided slope• syncline—a downfold that creates a U-shape
    7. 7. Crustal Fold Structures• monocline—a one-sided slope• syncline—a downfold that creates a U-shape• anticline—an upfold that creates an n-shape
    8. 8. Crustal Fold Structures• monocline—a one-sided slope• syncline—a downfold that creates a U-shape• anticline—an upfold that creates an n-shape• overturned fold—similar to an anticline, but tipped to one side
    9. 9. Crustal Fold Structures• monocline—a one-sided slope• syncline—a downfold that creates a U-shape• anticline—an upfold that creates an n-shape• overturned fold—similar to an anticline, but tipped to one side• overthrust fold—an overturned fold pushed completely over on its side, so that the entire fold lays on top of the section in front of it
    10. 10. FaultsEventually, even the plastic crust will break…
    11. 11. Normal Fault(tension stress)
    12. 12. Fault Block Mountains The Sierra Nevadas
    13. 13. Reverse Fault(compression stress)
    14. 14. Strike-slip/Transform/Transcurrent Fault (shear stress)
    15. 15. The San Andreas runs rightthrough the town of Hollister, CA…
    16. 16. Common Structures Associated with Transform Faults
    17. 17. Thrust Fault(compression stress—low-angle)
    18. 18. Earthquakes or Hypocenter
    19. 19. Earthquake Measurement
    20. 20. Earthquake Measurement Seismic waves—Energy waves propagated during an earthquake
    21. 21. Earthquake Measurement Seismic waves—Energy waves propagated during an earthquake Seismograph—Recording device for measuring the amount of shaking which occurs during an earthquake
    22. 22. Earthquake Measurement Seismic waves—Energy waves propagated during an earthquake Seismograph—Recording device for measuring the amount of shaking which occurs during an earthquake Seismogram—The printed record made by the seismograph
    23. 23. Quantitative vs. Qualitative Seismic Measurements
    24. 24. Quantitative vs. Qualitative Seismic Measurements
    25. 25. Quantitative vs. Qualitative Seismic Measurements• Quantitative—Objective, fact-based measurement; mathematical
    26. 26. Quantitative vs. Qualitative Seismic Measurements• Quantitative—Objective, fact-based measurement; mathematical
    27. 27. Quantitative vs. Qualitative Seismic Measurements• Quantitative—Objective, fact-based measurement; mathematical• Qualitative—Subjective; each person’s interpretation of the same event may be different
    28. 28. Measuring Seismic Waves
    29. 29. Measuring Seismic Waves• Richter Scale—A numerical expression of the amount of energy released during an earthquake event (Quantitative)
    30. 30. Measuring Seismic Waves• Richter Scale—A numerical expression of the amount of energy released during an earthquake event (Quantitative) – Based on the physical force exerted by the surface movement of earthquake waves
    31. 31. Measuring Seismic Waves• Richter Scale—A numerical expression of the amount of energy released during an earthquake event (Quantitative) – Based on the physical force exerted by the surface movement of earthquake waves – Logarithmic scale…the difference between one order of magnitude and the next represents 10 times the amount of force
    32. 32. Measuring Seismic Waves• Richter Scale—A numerical expression of the amount of energy released during an earthquake event (Quantitative) – Based on the physical force exerted by the surface movement of earthquake waves – Logarithmic scale…the difference between one order of magnitude and the next represents 10 times the amount of force – Only useful for expressing surface motion
    33. 33. Measuring Seismic Waves• Richter Scale—A numerical expression of the amount of energy released during an earthquake event (Quantitative) – Based on the physical force exerted by the surface movement of earthquake waves – Logarithmic scale…the difference between one order of magnitude and the next represents 10 times the amount of force – Only useful for expressing surface motion – Equations not accurate enough at high magnitude
    34. 34. Measuring Seismic Waves
    35. 35. Measuring Seismic Waves• Moment Magnitude Scale
    36. 36. Measuring Seismic Waves• Moment Magnitude Scale – More accurate at higher magnitudes
    37. 37. Measuring Seismic Waves• Moment Magnitude Scale – More accurate at higher magnitudes – Equations used to compare larger quakes (>4.0)--best for 7.0+ (Quantitative)
    38. 38. Measuring Seismic Waves• Moment Magnitude Scale – More accurate at higher magnitudes – Equations used to compare larger quakes (>4.0)--best for 7.0+ (Quantitative) – Based on:
    39. 39. Measuring Seismic Waves• Moment Magnitude Scale – More accurate at higher magnitudes – Equations used to compare larger quakes (>4.0)--best for 7.0+ (Quantitative) – Based on: • the size and extent of fault movement
    40. 40. Measuring Seismic Waves• Moment Magnitude Scale – More accurate at higher magnitudes – Equations used to compare larger quakes (>4.0)--best for 7.0+ (Quantitative) – Based on: • the size and extent of fault movement • the amount of stress necessary to overcome the friction holding the rocks together
    41. 41. Measuring Seismic Waves• Moment Magnitude Scale – More accurate at higher magnitudes – Equations used to compare larger quakes (>4.0)--best for 7.0+ (Quantitative) – Based on: • the size and extent of fault movement • the amount of stress necessary to overcome the friction holding the rocks together • and the average distance that the rocks slid apart along the fault.
    42. 42. Measuring Seismic Waves
    43. 43. Measuring Seismic Waves• Mercalli Scale
    44. 44. Measuring Seismic Waves• Mercalli Scale – Measures an earthquake’s intensity (Qualitative)
    45. 45. Measuring Seismic Waves• Mercalli Scale – Measures an earthquake’s intensity (Qualitative) – Based on what people feel
    46. 46. Measuring Seismic Waves• Mercalli Scale – Measures an earthquake’s intensity (Qualitative) – Based on what people feel – Uses questionnaires and personal accounts
    47. 47. Measuring Seismic Waves• Mercalli Scale – Measures an earthquake’s intensity (Qualitative) – Based on what people feel – Uses questionnaires and personal accounts • Good for:
    48. 48. Measuring Seismic Waves• Mercalli Scale – Measures an earthquake’s intensity (Qualitative) – Based on what people feel – Uses questionnaires and personal accounts • Good for: – Earthquakes of the past for which no other records exist
    49. 49. Measuring Seismic Waves• Mercalli Scale – Measures an earthquake’s intensity (Qualitative) – Based on what people feel – Uses questionnaires and personal accounts • Good for: – Earthquakes of the past for which no other records exist – Areas where existing development makes geologic studies more difficult
    50. 50. Measuring Seismic Waves• Mercalli Scale – Measures an earthquake’s intensity (Qualitative) – Based on what people feel – Uses questionnaires and personal accounts • Good for: – Earthquakes of the past for which no other records exist – Areas where existing development makes geologic studies more difficult – Can help urban agencies plan for future earthquakes in areas needing upgrades or retrofitting
    51. 51. Loma Prieta Quake, 1989
    52. 52. Loma Prieta Quake
    53. 53. Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)
    54. 54. Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)
    55. 55. Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)• Severely shook the San Francisco and Monterey Bay regions
    56. 56. Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)• Severely shook the San Francisco and Monterey Bay regions• Epicenter located near Loma Prieta peak in the Santa Cruz Mountains, approximately 14 km (9 mi) NE of Santa Cruz and 96 km (60 mi) S-SE of San Francisco
    57. 57. Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)• Severely shook the San Francisco and Monterey Bay regions• Epicenter located near Loma Prieta peak in the Santa Cruz Mountains, approximately 14 km (9 mi) NE of Santa Cruz and 96 km (60 mi) S-SE of San Francisco• The Pacific and North American Plates abruptly slipped as much as 2 meters (7 ft) along the San Andreas fault
    58. 58. Loma Prieta Quake• On October 17, 1989, at 5:04:15 p.m. (PDT)• Magnitude 6.9 (moment magnitude)• Severely shook the San Francisco and Monterey Bay regions• Epicenter located near Loma Prieta peak in the Santa Cruz Mountains, approximately 14 km (9 mi) NE of Santa Cruz and 96 km (60 mi) S-SE of San Francisco• The Pacific and North American Plates abruptly slipped as much as 2 meters (7 ft) along the San Andreas fault• The rupture began at a depth of 18 km (11 mi) and extended 35 km (22 mi) along the fault, but it did not break the surface of the Earth
    59. 59. Loma Prieta Quake, 1989
    60. 60. Seismic Waves
    61. 61. Seismic Waves• Body waves
    62. 62. Seismic Waves• Body waves – Travel deep beneath the surface
    63. 63. Seismic Waves• Body waves – Travel deep beneath the surface • P-waves
    64. 64. Seismic Waves• Body waves – Travel deep beneath the surface • P-waves • S-waves
    65. 65. Seismic Waves• Body waves – Travel deep beneath the surface • P-waves • S-waves• Surface waves
    66. 66. Seismic Waves• Body waves – Travel deep beneath the surface • P-waves • S-waves• Surface waves – Travel at or near the surface
    67. 67. Seismic Waves• Body waves – Travel deep beneath the surface • P-waves • S-waves• Surface waves – Travel at or near the surface • L-waves
    68. 68. Seismic Waves• Body waves – Travel deep beneath the surface • P-waves • S-waves• Surface waves – Travel at or near the surface • L-waves • R-waves
    69. 69. Seismic Waves P-waves: Pressure or Primary waves  Travel fastest  First to arrive  Travel through all mediums (solid, liquid, gas)  If big enough, they can be felt on the other side of the planet
    70. 70. Seismic Waves P-waves: Pressure or Primary waves  Travel fastest  First to arrive  Travel through all mediums (solid, liquid, gas)  If big enough, they can be felt on the other side of the planet
    71. 71. Seismic Waves S-waves: Secondary or Shear waves  Slower than P-waves  Second to arrive  Travel only through solids
    72. 72. Seismic Waves S-waves: Secondary or Shear waves  Slower than P-waves  Second to arrive  Travel only through solids
    73. 73. Seismic Waves S-waves: Secondary or Shear waves  Slower than P-waves  Second to arrive  Travel only through solids
    74. 74. Seismic Waves• Love waves – Push rocks from side to side as the motion of the wave follows a horizontal ellipse which travels forward
    75. 75. Seismic Waves• Rayleigh waves produce an up and down motion created by a forward roll, much like that of an oscillating water wave on the open ocean – Slower than Love waves • 10 times the speed of sound
    76. 76. Both L-waves and R-waves:
    77. 77. Both L-waves and R-waves:• Can travel only through solids
    78. 78. Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event
    79. 79. Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exponentially the further the focus is from the surface
    80. 80. Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exponentially the further the focus is from the surface• Motions do not dissipate quickly
    81. 81. Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exponentially the further the focus is from the surface• Motions do not dissipate quickly• May continue for an extended period at the tail end of a quake
    82. 82. Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exponentially the further the focus is from the surface• Motions do not dissipate quickly• May continue for an extended period at the tail end of a quake• Can travel much longer distances than body waves
    83. 83. Both L-waves and R-waves:• Can travel only through solids• May not be felt at every earthquake event• Motion decreases exponentially the further the focus is from the surface• Motions do not dissipate quickly• May continue for an extended period at the tail end of a quake• Can travel much longer distances than body waves• Tend cause the most damage to structures and to landforms prone to mass movement
    84. 84. Earthquakes and theRelationship to Plate Tectonics
    85. 85. Pinpointing an Earthquake
    86. 86. Pinpointing an Earthquake
    87. 87. Earthquake Hazard Map
    88. 88. Earthquake Hazards
    89. 89. Earthquake Hazards• Falling debris and rock material
    90. 90. Earthquake Hazards• Falling debris and rock material• Crumbling buildings
    91. 91. Earthquake Hazards• Falling debris and rock material• Crumbling buildings• Ground cracks
    92. 92. Earthquake Hazards• Falling debris and rock material• Crumbling buildings• Ground cracks• Broken bridges
    93. 93. Earthquake Hazards• Falling debris and rock material• Crumbling buildings• Ground cracks• Broken bridges• Landslides
    94. 94. Earthquake Hazards• Falling debris and rock material• Crumbling buildings• Ground cracks• Broken bridges• Landslides• Liquefaction
    95. 95. Earthquake Hazards• Falling debris and rock material• Crumbling buildings• Ground cracks• Broken bridges• Landslides• Liquefaction• Tsunamis
    96. 96. Liquefaction
    97. 97. Liquefaction• Liquefaction
    98. 98. Liquefaction• Liquefaction – (from Latin liquefacere meaning “to liquefy”)
    99. 99. Liquefaction• Liquefaction – (from Latin liquefacere meaning “to liquefy”) – Settling of solid material and rising of water normally stored between the pore spaces, turning surface material into quicksand
    100. 100. Liquefaction• Liquefaction – (from Latin liquefacere meaning “to liquefy”) – Settling of solid material and rising of water normally stored between the pore spaces, turning surface material into quicksand – Danger where the water table is near the surface and surface material consists of loose, unconsolidated, water-saturated sediments
    101. 101. Liquefaction• Liquefaction – (from Latin liquefacere meaning “to liquefy”) – Settling of solid material and rising of water normally stored between the pore spaces, turning surface material into quicksand – Danger where the water table is near the surface and surface material consists of loose, unconsolidated, water-saturated sediments • Land may subside
    102. 102. Liquefaction• Liquefaction – (from Latin liquefacere meaning “to liquefy”) – Settling of solid material and rising of water normally stored between the pore spaces, turning surface material into quicksand – Danger where the water table is near the surface and surface material consists of loose, unconsolidated, water-saturated sediments • Land may subside • Structures (and people!) sink
    103. 103. Liquefaction• Liquefaction – (from Latin liquefacere meaning “to liquefy”) – Settling of solid material and rising of water normally stored between the pore spaces, turning surface material into quicksand – Danger where the water table is near the surface and surface material consists of loose, unconsolidated, water-saturated sediments • Land may subside • Structures (and people!) sink – Only occurs during shaking
    104. 104. Liquefaction• Liquefaction – (from Latin liquefacere meaning “to liquefy”) – Settling of solid material and rising of water normally stored between the pore spaces, turning surface material into quicksand – Danger where the water table is near the surface and surface material consists of loose, unconsolidated, water-saturated sediments • Land may subside • Structures (and people!) sink – Only occurs during shaking • After shaking, settled material becomes solid again and any water on the surface either percolates back down or runs off into streams.
    105. 105. Liquefaction
    106. 106. Liquefaction under Kawagishi-cho apartment buildings, Niigata quake, 1964
    107. 107. San Francisco: Original Shoreline Liquefaction Potential?
    108. 108. The Pacific Ring of Fire
    109. 109. The Pacific Ring of Fire
    110. 110. Oceanic-Oceanic Subduction
    111. 111. Oceanic-Oceanic SubductionProduces: – Big earthquakes and volcanic islands – A deep ocean trench
    112. 112. What Does a Tidal Wave Look Like?
    113. 113. What Does a Tidal Wave Look Like? Truro, Nova Scotia, Canada
    114. 114. You meant a Tsunami, right?
    115. 115. You meant a Tsunami, right?
    116. 116. You meant a Tsunami, right?
    117. 117. Oceanic-Oceanic SubductionProduces: – Big earthquakes and volcanic islands, called “island arcs” – A deep ocean trench – High potential for tsunamis
    118. 118. Tsunamis
    119. 119. Tsunamis• Waves caused by undersea volcanic or tectonic events (earthquakes)
    120. 120. Tsunamis• Waves caused by undersea volcanic or tectonic events (earthquakes)• Unnoticed by observers on the open ocean
    121. 121. Tsunamis• Waves caused by undersea volcanic or tectonic events (earthquakes)• Unnoticed by observers on the open ocean• Can reach up to 100 feet in height when they enter a coastal zone
    122. 122. Tsunamis• Waves caused by undersea volcanic or tectonic events (earthquakes)• Unnoticed by observers on the open ocean• Can reach up to 100 feet in height when they enter a coastal zone• Can be anticipated wherever deep-focus undersea earthquakes occur
    123. 123. Tsunamis• Waves caused by undersea volcanic or tectonic events (earthquakes)• Unnoticed by observers on the open ocean• Can reach up to 100 feet in height when they enter a coastal zone• Can be anticipated wherever deep-focus undersea earthquakes occur• Can be detected with special sensors, allowing time for evacuation
    124. 124. Sumatra Quake, Dec. 26, 2004http://www.nytimes.com/packages/khtml/2004/12/26/ international/20041227_QUAKE_FEATURE.html

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