Today’s plan - Arizona State Universityarrowsmith310.asu.edu/Lectures/GLG310_Lecture9...and_globalstres… · Today’s plan •Continue Force, Stress, ... •Be sure to cross reference

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GLG310 Structural Geology

Today’s plan

• Continue Force, Stress, and Strength

(Chapter 3) [continue reading Chapter 3]

• Be sure to cross reference the lecture and

the textbook

• Stretch a bit into faults and stress

26 September 2013 GLG310 Structural Geology

2

Classification of

faults

26 September 2013

Fracture

26 September 2013 GLG310 Structural Geology

3

26 September 2013

Andersonian Faulting

Theory

• Key assumptions:

– Earth’s surface is a free surface (so it has no

shear tractions acting along it). Therefore, s1,

s2, s3 must be either parallel or perpendicular

to it.

– A fault will slip in the direction of maximum

resolved shear traction

By E. M. Anderson

(1st ed. 1942, 2nd ed. 1951)

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Andersonian Faulting

Theory

26 September 2013 GLG510 Advanced Structural

Geology

Andersonian

Faulting

Theory

Rowland and

Duebendorfer

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Andersonian Faulting

Theory

-Engelder, 1993, Stress regimes in the lithosphere, Princeton Univ. Press

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26 September 2013 GLG310 Structural Geology

Relative stress magnitudes and faulting regimes

(from Reservoir Geomechanics by Zoback--http://www.amazon.com/Reservoir-

Geomechanics-Mark-D-Zoback/dp/0521770696)

26 September 2013

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26 September 2013

World Stress Map

http://www.world-stress-map.org/

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North America Stress Map

http://www.world-stress-map.org/