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Making Waves: Seismic Waves Activities and Demonstrations

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Making Waves: Seismic Waves Activities and Demonstrations

Larry Braile, Purdue University

web.ics.purdue.edu/~braile

Sheryl Braile, Happy Hollow School

West Lafayette, IN

CSTA Conference, October 2009

Palm Springs, CA

This PowerPoint file: http://web.ics.purdue.edu/~braile/new/SeismicWaves.ppt

- 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.

- 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

Elasticity – a property of materials that results

In wave propagation and earthquakes

* Difference in length of spring before and after adding mass.

Slinky and human wave demo and wave tank and elasticity experiments:

http://web.ics.purdue.edu/~braile/edumod/slinky/slinky.htm

http://web.ics.purdue.edu/~braile/edumod/slinky/slinky.doc

http://web.ics.purdue.edu/~braile/edumod/slinky/slinky.pdf

Characteristics of Seismic Waves

Characteristics of Seismic Waves

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.

- 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.

The 5-slinky model for demonstrating that seismic

waves propagate in all directions and the variation

of travel time with distance.

The human wave demonstration illustrating P and S

wave propagation in solids and liquids.

Wave animations

Animation courtesy of Dr. Dan Russell, Kettering University

http://www.kettering.edu/~drussell/demos.html

Seismic Wave animations(Developed by L. Braile)http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.htm

Animation courtesy of Dr. Dan Russell, Kettering University

http://www.kettering.edu/~drussell/demos.html

Direction of propagation

Animation courtesy of Dr. Dan Russell, Kettering University

http://www.kettering.edu/~drussell/demos.html

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.

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, Earth’s 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.

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.

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.

You can download the animations separately to run more efficiently: (http://web.ics.purdue.edu/~braile/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/WaveDemo.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/as1lessons/UsingAmaSeis/UsingAmaSeis.htm

The IRIS Seismographs in Schools program:

http://www.iris.edu/hq/sis

IRIS AmaSeis

Software

24-Hour Screen Display

Extracted Seismogram

The AS-1 Seismometer

Teaching Modules and Tutorials:

http://web.ics.purdue.edu/~braile/edumod/as1lessons/as1lessons.htm

From Alan Jones, SUNY, Binghamton

http://bingweb.binghamton.edu/~ajones/

Earthquake

*

Cross Section

Through Earth

Wavefront

Ray Path

Stations for

Seismograms

Seismograph

Ray Path is perpendicular

to wavefront