Seismic Waves

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Making Waves Seismic Waves Activities and
Demonstrations
Larry Braile, Purdue University braile_at_purdue.edu,
web.ics.purdue.edu/braile Sheryl Braile,
Happy Hollow School West Lafayette,
IN sjbraile_at_gmail.com CSTA Conference, October
2011 Pasadena, CA
This PowerPoint file http//web.ics.purdue.edu
/braile/new/SeismicWaves.ppt     
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Seismic Waves

• Slinky P, S, Rayleigh, Love waves
• Reflection and transmission energy carried by
  waves elastic rebound/plate motions and the
  slinky 5-slinky model waves in all directions,
  travel times to different distances.
• Human wave demo P and S waves in solids and
  liquids.
• Seismic wave animations P, S, Rayleigh, Love
  waves wave motion wave propagation activity.
• Seismograms Viewing seismograms on your
  computer (AmaSeis software).
• Seismic Waves software Wave propagation through
  the Earth.

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Why use several approaches for teaching about
seismic waves?

• Fundamental concept (worth spending time on)
• Different approaches for different settings or
  size of group
• Different learning styles
• Reinforce with more than one approach
• Demonstrations, animations and hands-on
  activities
• Use one or more approach for authentic assessment

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Elasticity a property of materials that
results In wave propagation and earthquakes
Difference in length of spring before and after
adding mass.
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(No Transcript)
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Slinky and human wave demo and wave tank and
elasticity experiments http//web.ics.purdue.edu/
braile/edumod/slinky/slinky.htm http//web.ics.pu
rdue.edu/braile/edumod/slinky/slinky.doc http//w
eb.ics.purdue.edu/braile/edumod/slinky/slinky.pdf

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Characteristics of Seismic Waves
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Characteristics of Seismic Waves
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A simple wave tank experiment a ping pong ball
is dropped onto the surface of the water small
floats aid viewing of the waves distance marks
on the bottom of the container allow calculation
of wave velocity.
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Seismic waves and the slinky (also, see the
4-page slinky write-up at http//web.ics.purdue.e
du/braile/edumod/slinky/slinky4.doc)

• P and S waves
• Love and Rayleigh waves
• Wave reflection and transmission
• Elastic rebound
• Waves carry energy
• The five slinky model (waves in
• all directions and different travel
• times to different locations the
• way that earthquakes are located)

Seismic waves carry energy. Observe the shaking
of the model building when P and S waves are
propagated along the slinky.
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The 5-slinky model for demonstrating that
seismic waves propagate in all directions and the
variation of travel time with
distance.
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The human wave demonstration illustrating P and
S wave propagation in solids and liquids.
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The people wave (Dan Russell)
Wave animations

Seismic Wave
animations

(L. Braile) http//web.ics.purdue.edu/braile/ed
umod/waves/WaveDemo.htm

• Animation courtesy of Dr. Dan Russell, Kettering
  Univ.
• http//www.kettering.edu/drussell/demos.html

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Dan Russell animations Rayleigh wave
Direction of propagation

• Animation courtesy of Dr. Dan Russell, Kettering
  University
• http//www.kettering.edu/drussell/demos.html

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Compressional Wave (P-Wave) Animation
Deformation propagates. Particle motion consists
of alternating compression and dilation.
Particle motion is parallel to the direction of
propagation (longitudinal). Material returns to
its original shape after wave passes.
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Shear Wave (S-Wave) Animation
Deformation propagates. Particle motion consists
of alternating transverse motion. Particle
motion is perpendicular to the direction of
propagation (transverse). Transverse particle
motion shown here is vertical but can be in any
direction. However, Earths layers tend to cause
mostly vertical (SV in the vertical plane) or
horizontal (SH) shear motions. Material returns
to its original shape after wave passes.
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Rayleigh Wave (R-Wave) Animation
Deformation propagates. Particle motion consists
of elliptical motions (generally retrograde
elliptical) in the vertical plane and parallel to
the direction of propagation. Amplitude
decreases with depth. Material returns to its
original shape after wave passes.
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Love Wave (L-Wave) Animation
Deformation propagates. Particle motion consists
of alternating transverse motions. Particle
motion is horizontal and perpendicular to the
direction of propagation (transverse). To aid in
seeing that the particle motion is purely
horizontal, focus on the Y axis (red line) as the
wave propagates through it. Amplitude decreases
with depth. Material returns to its original
shape after wave passes.
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You can download the animations separately to run
more efficiently (http//web.ics.purdue.edu/brai
le/edumod/waves/WaveDemo.htm). A complete
PowerPoint presentation on the Seismic wave
animations is also available at
http//web.ics.purdue.edu/braile/edumod/waves/Wav
eDemo.ppt

• Demonstrate the AmaSeis software for displaying
  and analyzing seismograms software available at
• http//bingweb.binghamton.edu/ajones/
• A tutorial on AmaSeis and links to seismograms
  that can be downloaded and viewed in AmaSeis
  available at
• http//web.ics.purdue.edu/braile/edumod/as1lesson
  s/UsingAmaSeis/UsingAmaSeis.htm
• IRIS Seismographs in Schools program
  http//www.iris.edu/hq/sis
• IRIS Wave Visualizations
• http//www.iris.edu/hq/programs/education_and_outr
  each/visualizations
• USGS/SCEC SAF EQ Simulations
• http//earthquake.usgs.gov/regional/nca/simulation
  s/shakeout/

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(developed by Alan Jones, SUNY Binghamton, NY)
IRIS AmaSeis Software
24-Hour Screen Display
Extracted Seismogram
The AS-1 Seismometer
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Teaching Modules and Tutorials http//web.ics.pur
due.edu/braile/edumod/as1lessons/as1lessons.htm
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The Seismic Waves program

• From Alan Jones, SUNY, Binghamton
• http//bingweb.binghamton.edu/ajones/

Earthquake

Wavefront
Cross Section Through Earth
Ray Path
Stations for Seismograms
Seismograph
Ray Path is perpendicular to wavefront
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Time T1
Earthquake

Wavefront
Cross Section Through Earth
Ray Path
Stations for Seismograms
Seismograph
Ray Path is perpendicular to wavefront
Time T2
Earthquake

Wavefront
Cross Section Through Earth
Ray Path
Stations for Seismograms
Seismograph
Ray Path is perpendicular to wavefront
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Earths interior structure and seismic raypaths
that are used to determine the Earth structure.
http//www.iris.edu/hq/files/programs/education_an
d_outreach/lessons_and_resources/images/ExplorEart
hPoster.jpg