geology 3120 - faults
DESCRIPTION
Geology 3120 - Faults. Outline. Fault components Slip verses separation Faulting styles Piercing points Calculating slip from piercing points Fault exercises. Kobe Earthquake Fault Rupture Museum. Fault Components. Footwall Hanging wall Fault plane, fault surface. - PowerPoint PPT PresentationTRANSCRIPT
Geology 3120 - Geology 3120 - FaultsFaults
OutlineOutline
• Fault components
• Slip verses separation
• Faulting styles
• Piercing points
• Calculating slip from piercing points
• Fault exercises
Kobe Earthquake Fault Rupture Kobe Earthquake Fault Rupture
MuseumMuseum
Fault ComponentsFault Components
• Footwall
• Hanging wall
• Fault plane, fault surface
Footwall
Hanging wall
Slip verses SeparationSlip verses Separation
Pre-faulted block Faulted block Eroded block
• Slip - actual relative displacement between two points that occupied
the same location before faulting
• Separation - apparent relative displacement between two points that
may have occupied the same location before faulting
Slip Separation
Faulting StylesFaulting Styles
Normal
Thrust
Strike-slip
Dip-slip
Dip-slip
Strike-slip
Faulting StylesFaulting Styles
Oblique-slip: a combination of dip-slip and strike-slip
Fault Exercises - ExampleFault Exercises - Example
Pre-faulted block Faulted block Eroded block
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Fault Exercises - ExampleFault Exercises - Example
Pre-faulted block Faulted block Eroded block
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Fault Exercises - ExampleFault Exercises - Example
Pre-faulted block Faulted block Eroded block
Fault ExercisesFault Exercises
• Study the examples in ia, ib, ic
• Fill in the beds in the remaining six diagrams keeping in mind the effects faulting and erosion
Example 2Example 2
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Pre-faulted block Faulted block Eroded block
Example 2Example 2
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Pre-faulted block Faulted block Eroded block
Example 2Example 2
Pre-faulted block Faulted block Eroded block
Example 3Example 3
Pre-faulted block Faulted block Eroded block
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Example 3Example 3
Pre-faulted block Faulted block Eroded block
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Example 3Example 3
Pre-faulted block Faulted block Eroded block
Example 4Example 4
Pre-faulted block Faulted block Eroded block
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Example 4Example 4
Pre-faulted block Faulted block Eroded block
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Example 4Example 4
Pre-faulted block Faulted block Eroded block
Piercing Piercing
PointsPoints
Calculating SlipCalculating Slip
AA
BB
Given:Given:
Position coordinates (x,y,z) in metersPosition coordinates (x,y,z) in meters
A (2, 3, 10)A (2, 3, 10)
B (7,11, 3)B (7,11, 3)
Problem:Problem: Determine slipDetermine slip
(trend, plunge, magnitude)(trend, plunge, magnitude)
Calculating SlipCalculating Slip
X
TrendTrend
X = (7-2) = 5 mX = (7-2) = 5 m
Y = (11-3) = 8 mY = (11-3) = 8 m
M = (M = (XX22+ + YY22))0.50.5 = (5 = (522+8+822))0.5 0.5 = 9.4 m= 9.4 m
Magnitude = 9.4 mMagnitude = 9.4 m
Tan Tan = = Y/ Y/ XX
= Tan= Tan-1-1(8/5)(8/5)
= 58°= 58°
Azimuth = 90°-58° = 032°Azimuth = 90°-58° = 032°
Y
A (2, 3, 10)A (2, 3, 10)
B (7,11, 3)B (7,11, 3)
xx
yyNN
00
PlungePlunge
M = 9.4 mM = 9.4 m
Z = (10-3) = 7 mZ = (10-3) = 7 m
S = (S = (22+ + ZZ22))0.50.5 = (9.4 = (9.422+7+722))0.5 0.5 = 11.7 m= 11.7 m
Total slip [S] = 11.7 mTotal slip [S] = 11.7 m
Tan Tan = = Z/ MZ/ M
= Tan= Tan-1-1(7/9.4)(7/9.4)
= 37°= 37°
Plunge value = 37°Plunge value = 37°
SolutionSolution: slip vector 37°,032°; 11.7 m magnitude: slip vector 37°,032°; 11.7 m magnitude
Calculating SlipCalculating Slip
SZ
xx
zzSWSW
00
NENE