1. Seismic Waves & Refraction Overview GEOS 322 Spring 2009

2. Outline Seismic Wave Particle Motion Examples Refraction Basics Discuss the last quiz

3. P-Wave Particle Motion http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.htm

4. S-Wave Particle Motion http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.htm

5. Rayleigh-Wave Particle Motion http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.htm

6. Love-Wave Particle Motion http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.htm

7. On to refraction Sources include a power point presentation from IRIS – http://www.iris.edu/hq/resource/how_shallow_e arth_structure_is_determined http://www.iris.edu/hq/resource/how_shallow_e arth_structure_is_determined – http://web.utah.edu/thorne/animations.html http://web.utah.edu/thorne/animations.html

11. The first head wave is a reflected wave at the critical angle i c

12. The Head wave moves along the surface at the SPEED OF THE LOWER LAYER!!!

13. Time Distance Direct wave: Slope is 1/v 1 The cross-over distance, x cross, is related to the depth to the boundary! Head wave: Slope is 1/v 2 x cross

14. Refraction Movie

15. Model from movie

16. Direct Wave Reflected Wave

21. Chapter 4 Quiz A A C C B B