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Class Outline

Learn basic techniques and principles in structural geology, deformation mechanisms, continuum mechanics, and earthquake focal mechanisms in this course. Includes hands-on field measurements and mapping using stereographic projections.

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Class Outline

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  1. Class Outline • Deformation of the lithosphere, an overview • Basic Techniques in Structural Geology and Tectonics • Basic of Continuum mechanics- strain • Basic of Continuum mechanics- stress • Deformation Mechanism…

  2. II. Basic Techniques in Structural Geology • Fundamental principles • Field measurements and mapping • Stereographic projections • …

  3. Representations of lines and planes.. Line as a pole.. Plane as great circle..

  4. Stereographic equal-angle projection (Wulff’s Stereonet) Lambert’s equal area projection (Schmidt;s stereonet)

  5. Spherical coordinate frame… Polar Net (N is the pole of the coordinate net)

  6. Stereographic nets (equal-angle nets or Wulff)’s stereonets) NB: Only half of the sphere is generally plotted Polar Net (polar axis vertical) Meridional Net (polar axis horizontal)

  7. Equal-area nets- Schmidt Polar Net (polar axis vertical) Meridional Net (polar axis horizontal)

  8. Projecting data… B(B’): 72,0 (252,0) C:72,45

  9. B (B’): 72,0 (252,0) C:72,45 Q: 227, 43 (e.g., dip direction of a bed S: 47, 47 (pole to bedding defined by Q)

  10. Paper & pencil..

  11. Measuring angles on a sterographic projection… P: 272,45

  12. Fold axis of (Cylindrical) fold might be determined from the intersection of bedding planes.

  13. Folded beddingas poles &as great circles.. β diagram n(n-1)/2 intersections Π diagram

  14. Elastic Rebound Theory Interseismic strain (locked fault gets stressed) Co-seismic strain (fault failure during Earthquake Posterior to Last earthquake

  15. First Motions

  16. P-wave Radiation Pattern

  17. Earthquake focal mechanisms will always have variations in polarity. Some stations will have first motion up, others first motion down.

  18. First Motions: Denali Earthquake

  19. Earthquake Focal Mechanisms

  20. Earthquake Focal Mechanisms

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