• Like
Lecture11 earthquakes
Upcoming SlideShare
Loading in...5
×

Lecture11 earthquakes

  • 295 views
Uploaded on

 

More in: Technology , Education
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
295
On Slideshare
0
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
11
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Earthquakes
  • 2.  
  • 3. Global Seismicity
  • 4. Continental Drift Animation based on paleomaps from University of Texas Arlington
  • 5. Plate tectonics: predicting the future
  • 6. Plate tectonics in the future: 50 my
    • Australia will straddle the equator
    • E. Africa will form new continent
    • Antarctica will swing off the south pole
    • Mediterranean will close off
    • Atlantic Ocean will grow
    • Pacific Ocean will shrink
  • 7. Global Seismicity
  • 8. Rocks are stressed too…
    • Rock stress: from tectonic forces, gravity, and weight of rocks above
    • Types of stress
    • Tension (stretching)
    • Compression (shortening)
    • Shear (twisting or tearing)
  • 9. Strain
    • = how rocks respond to stress
    • 2 types
    • folding (bending)
    • faulting (breaking)
    depends on rock composition, pressure, and rock characteristics (brittle vs. ductile)
  • 10. Types of folds
    • Anticline
      • simple upfold
      • layers slope down from axis
      • younger on outside
    • Syncline
      • simple downfold
      • layers slope up from axis
      • younger on inside
    younger older younger older
  • 11. Types of folds syncline anticline overturned anticline
  • 12. Types of Faults Tension Compression Shear Stretching Shortening Twisting
  • 13. Faulting
    • = rocks on either side of a fracture are displaced relative to each other
    • Earthquake: caused by sudden release of energy along a fault
  • 14. Anatomy of a fault
    • Fault scarp = steep cliffs that make up the edge of a displaced block
  • 15. 3 Types of Faults
    • Normal
      • tension
    • Reverse
      • compression
    • Strike-slip (transcurrent)
      • shearing
      • lateral displacement
  • 16. 3 Types of Faults
  • 17. 3 Types of Faults Divergent Plate Boundaries
  • 18. 3 Types of Faults Convergent Plate Boundaries
  • 19. 3 Types of Faults Transform Plate Boundaries
  • 20. Earthquakes
    • = vibration in the Earth
    • produced by shockwaves from sudden movements along faults
    Seismic = pertaining to earthquakes
  • 21. Focus vs epicenter
    • Focus = center of fault motion
    • Epicenter = surface directly above focus
  • 22. Seismometer
  • 23. Seismogram
  • 24. Richter Scale Scale is exponential For every increase of 1 in the Richter scale, the wave amplitude increases x10 Exponential decay Exponential growth y = y 0 e -kx y = e kx
  • 25. a = 10 M Where M is Richter magnitude, and a is wave amplitude M = log 10 (a) Which is the same as Richter Scale Scale is exponential For every increase of 1 in the Richter scale, the wave amplitude increases x10
  • 26. But wave amplitude is not the same as energy released . (see pg 408 in Strahler) E = 10 (4.8+1.5M) = 10 4.8 ·10 1.5M Where M is Richter magnitude, and E is energy released So for every increase of 1 in the Richter magnitude, energy increases x 32 Richter Scale
  • 27. How much energy is released?
    • For example, the earthquake that caused the Indian Ocean tsunamis on Boxing Day 2004 (12/26/04) measured 9 on the Richter scale
    • How much energy was released by this quake?
      • E = 10 (4.8 + 1.5M)
  • 28. The Boxing Day Quake
    • How much energy was released by this quake?
    • E = 10 (4.8 + 1.5M)
    • = 10 (4.8 + 1.5(9))
    • = 10 (4.8 + 13.5)
    • = 10 (18.3) = 1.99 x 10 18 J
    For comparison, the average U.S. electric power consumption rate is 3 x 10 12 J/sec