260 likes | 523 Views
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.
E N D
Outline • Fault components • Slip verses separation • Faulting styles • Piercing points • Calculating slip from piercing points • Fault exercises
Fault Components • Footwall • Hanging wall • Fault plane, fault surface Hanging wall Footwall
Slip verses Separation Separation Slip 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
Faulting Styles Normal Dip-slip Thrust Dip-slip Strike-slip Strike-slip
Faulting Styles Oblique-slip: a combination of dip-slip and strike-slip
Fault Exercises - Example ?? ?? Pre-faulted block Faulted block Eroded block
Fault Exercises - Example ?? Pre-faulted block Faulted block Eroded block
Fault Exercises - Example Pre-faulted block Faulted block Eroded block
Fault 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 2 ?? ?? Pre-faulted block Faulted block Eroded block
Example 2 ?? Pre-faulted block Faulted block Eroded block
Example 2 Pre-faulted block Faulted block Eroded block
Example 3 ?? ?? Pre-faulted block Faulted block Eroded block
Example 3 ?? Pre-faulted block Faulted block Eroded block
Example 3 Pre-faulted block Faulted block Eroded block
Example 4 ?? ?? Pre-faulted block Faulted block Eroded block
Example 4 ?? Pre-faulted block Faulted block Eroded block
Example 4 Pre-faulted block Faulted block Eroded block
Calculating Slip Given: Position coordinates (x,y,z) in meters A (2, 3, 10) B (7,11, 3) Problem: Determine slip (trend, plunge, magnitude) A B
Calculating Slip N Trend DX = (7-2) = 5 m DY = (11-3) = 8 m M = (DX2+ DY2)0.5 = (52+82)0.5 = 9.4 m Magnitude = 9.4 m Tan Q = DY/ DX Q = Tan-1(8/5) Q = 58° Azimuth = 90°-58° = 032° y A (2, 3, 10) B (7,11, 3) B M DY Q DX A 0 x
Calculating Slip SW NE Plunge M = 9.4 m DZ = (10-3) = 7 m S = (M2+ DZ2)0.5 = (9.42+72)0.5 = 11.7 m Total slip [S] = 11.7 m Tan f = DZ/ M f = Tan-1(7/9.4) f = 37° Plunge value = 37° Solution: slip vector 37°,032°; 11.7 m magnitude z A M f DZ S B 0 x