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Earthquakes IV: ERT, Waves

Waves

  • wavelength: distance over which the wave repeats

  • amplitude: distance from undisturbed position to point of max displacement (crest or trough)

  • frequency: number of waves that pass a given point in a certain amount of time

    • higher frequency waves attenuate more quickly than lower frequency waves

Seismic Waves

  • in an earthquake, energy is released when movement begins at the hypocenter

  • the energy moves outwards as seismic waves through the earth

    • like sound waves in a rock

  • body waves: travel through the (body of) earth

    • p-waves

    • s-waves

  • surface waves: travel near surface only

    • love waves

    • Rayleigh waves

Body Waves

  • travel through (body of) earth

  • faster than surface waves

  • generally not damaging to buildings

  • can travel across/around the earth

  • 2 types: p and s waves

P-Waves

  • p = primary (or pressure)

  • fastest, they arrive first\

  • wave motion: parallel to direction of wave propagation

S-Waves

  • s = secondary (or shear)

  • slower than P-waves, but still much faster than surface waves

  • wave motion: perpendicular to direction of wave propagation

Surface Waves

  • travel near the surface only

  • slower than body waves

  • carry energy for greater distances away from the epicenter

  • very damaging to buildings

  • 2 types: love an Rayleigh waves

Love Waves

  • first described by british mathematician A.E.H Love

  • much slower than body waves

  • move side to side, perpendicular to direction of wave propagation

Rayleigh Waves

  • predicted to exist by Lord Rayleigh

  • much slower than body waves

  • move backwards- rotating, elliptical motion

Earthquakes IV: ERT, Waves

Waves

  • wavelength: distance over which the wave repeats

  • amplitude: distance from undisturbed position to point of max displacement (crest or trough)

  • frequency: number of waves that pass a given point in a certain amount of time

    • higher frequency waves attenuate more quickly than lower frequency waves

Seismic Waves

  • in an earthquake, energy is released when movement begins at the hypocenter

  • the energy moves outwards as seismic waves through the earth

    • like sound waves in a rock

  • body waves: travel through the (body of) earth

    • p-waves

    • s-waves

  • surface waves: travel near surface only

    • love waves

    • Rayleigh waves

Body Waves

  • travel through (body of) earth

  • faster than surface waves

  • generally not damaging to buildings

  • can travel across/around the earth

  • 2 types: p and s waves

P-Waves

  • p = primary (or pressure)

  • fastest, they arrive first\

  • wave motion: parallel to direction of wave propagation

S-Waves

  • s = secondary (or shear)

  • slower than P-waves, but still much faster than surface waves

  • wave motion: perpendicular to direction of wave propagation

Surface Waves

  • travel near the surface only

  • slower than body waves

  • carry energy for greater distances away from the epicenter

  • very damaging to buildings

  • 2 types: love an Rayleigh waves

Love Waves

  • first described by british mathematician A.E.H Love

  • much slower than body waves

  • move side to side, perpendicular to direction of wave propagation

Rayleigh Waves

  • predicted to exist by Lord Rayleigh

  • much slower than body waves

  • move backwards- rotating, elliptical motion

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