EARTHQUAKE HAZARDS

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    Ryo

    Cards (20)

    • ● refers to a force called shock
      ● shaking of the ground caused by sudden motions along
      fractures in the Earth’s crust
      ● generates weak to strong shaking on the Earth’s surface
      ○ movement of rock materials underneath
      Earthquakes
    • Causes of earthquakes:
      • movement of tectonic plates
      • volcanic activity
      • man-made disturbances
    • Which part of an earthquake is:
      ★ fracture in the rocks that make up the Earth’s crust
      ★ where earthquakes occur
      ★ planar features
      Fault
    • Which part of an earthquake is:
      ★ point at the surface of the Earth directly above the focus
      ★ where the shaking is most intense
      Epicenter
    • Which part of an earthquake is:
      ★ point within the Earth where an earthquake rupture
      starts
      ★ marks the origin of the earthquake
      Focus (Hypocenter)
    • Which part of an earthquake is:
      ★ constantly moving
      ★ massive rocks that make up the outer layer of the
      Earth’s surface
      ★ movement along faults triggers earthquakes
      ★ earthquakes occur when plates interact with each other
      Plates
    • Which part of an earthquake is:
      ★ waves that transmit energy released by the earthquake
      ★ causes the shaking of ground
      ★ energy released from the focus
      Seismic Waves
    • ➢ smaller earthquakes that occur within the vicinity of the
      main shock
      ★ follows the initial rupture
      ➢ caused by the re-adjustment of stress along the fault
      system
      Aftershocks
    • Type of fault:
      ★ faults that result from horizontal tension stresses in
      brittle rocks
      ‣ pull rocks apart
      ★ hanging-wall block moves down relative to the footwall
      block
      ★ divergent plate boundaries
      ‣ plates are moving away from each other
      Normal Fault
    • Type of fault:
      ★ faults that result from horizontal compressional stresses
      in brittle rocks
      ★ hanging-wall block moves up relative to the footwall
      block
      ★ convergent plate boundaries
      ‣ plates are colliding
      Reverse Fault
    • Type of fault:
      ★ special case of reverse fault
      ‣ dip of the fault is less than 45°
      ★ hanging wall block move up and over the footwall block
      ★ can have considerable displacement
      ★ results in older rock layers overlying lower rock layers
      ★ compressional tectonic settings
      ‣ collision mountain belts
      Thrust Fault
    • Type of fault:
      ★ faults that do not break the surface
      ‣ no visible surface rupture
      ★ rocks above the fault behaved in ductile function
      ★ rocks fold over the tip of the fault
      ★ can be only detected through geophysical techniques
      ★ poses seismic hazards due to stress
      Blind Faults
    • Type of fault:
      ★ faults where the motion has taken place along a
      horizontal direction
      ★ pushing rock blocks past each other
      ★ parallel to the strike of the faults
      ‣ along the dip direction of the faults
      ★ minimal vertical displacement
      ★ transform plate boundaries
      ‣ plates slide horizontally past each other
      ★ Varieties:
      1. Left-Lateral Strike Slip Fault
      ○ block on the other side moves to the left
      b. Right-Lateral Strike Slip Fault
      ○ block on the other side moves to the right
      Strike Slip Faults
    • Effects of an earthquake:
      • one of the most notable effects of the energy from the hypocenter
      • mostly affects the concrete structure from the surface
      • energy is transmitted in the from of seismic waves
      Ground Shaking
    • 3 Classifications of Seismic Waves
      P-waves, S-waves, Surface waves
    • Effects of an earthquake:
      • tension cracks
      • a phenomenon where ground movement occurs and the surface of the ground breaks
      • commonly present in areas located near or along fault lines
      Ground rupture or fissures
    • Effects of an earthquake:
      • The sediment composition becomes "liquefied" in the sense that it assumes the dynamics of water flowing
      Liquefaction
    • Effects of an earthquake:
      ★ land subsidence or sinking of the ground
      ★ major factor in an area’s susceptibility to flooding
      ‣ low-lying coastal areas and river deltas
      ★ precursor for the development of sinkholes
      ‣ can unexpectedly collapse
      Earthquake-Induced Ground Subsidence
    • Effects of an earthquake:
      • Came from the Japanese term "tsu" - harbor, and "nami" - waves
      • a wave or series of waves in a wave train generated by the sudden, vertical displacement of a column of water
      Tsunami
    • Effects of an earthquake:
      • landslides are mass movement of rock, soil, and debris down a slope due to gravity
      Earthquake-Induced Landslide
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