Earthquake and Seismic Waves Lecture

Overview

• Presentation on modeling earthquakes using a surface-level approach.
• Introduction to the concept of faults and seismic waves.

Faults and Earthquake Initiation

• Fault is relatively shallow compared to Earth's length.
• Earthquake starts on Earth's surface and travels through the substance.

Seismic Waves

P-Waves (Primary Waves)

• Characteristics:
  • Fast traveling.
  • Travel through solids and liquids.
  • Cause particles to bump into neighboring particles.
• Modeling with Slinky:
  • P-waves cause the rings to bunch together and move.
  • Bunching moves down the slinky, simulating travel.
  • P-waves are the fastest seismic waves.

S-Waves (Secondary Waves)

• Characteristics:
  • Move in a side-to-side motion.
  • Only travel through solids, not liquids.
• Modeling with Slinky:
  • Slinky moves side to side, demonstrating S-wave motion.
  • Energy can cause the movement to bounce back.

Comparison of P-Waves and S-Waves

• Speed Differences:
  • P-waves move faster than S-waves in reality.
  • In the slinky model, friction affects speed perception.

Limitations of the Slinky Model

• The model works to a certain extent but has limitations.
• Friction Impact:
  • Friction in the slinky affects the perceived speed of waves.
  • Thin edge of slinky has less friction moving side to side.
  • More friction when pushing against the floor.

Discussion Points

• Why the model does not accurately show P-wave speed advantage.
• Effect of friction in altering wave speed in the model.
• Student discussion on the friction influence.

Conclusion

• The slinky model is helpful but not completely accurate in representing seismic wave behavior due to friction.