Answer the following
questions:
QUESTION 1
Put false
(X) or true (√) at the front of Five of the following statements:
(20 marks)
|
1- σ2
is generally parallel to the strike of normal fault.
|
( √ )
|
|
2- Strain
depends on the rock properties.
|
( √ )
|
|
3- The
structures formed by pure shear have the en echelon arrangement.
|
( x )
|
|
4- In
the heterogeneous strain, the original straight lines remain straight after
deformation.
|
( x )
|
|
5- Strain
analysis requires a knowledge of the original undeformed state of the
rock materials.
|
( √ )
|
|
6- (λ1) is the
maximum direction of extension in strain ellipsoid.
|
( √ )
|
QUESTION 2
Fill in
the spaces of Five of the following statements: (20 marks)
1- σ3> σ2.> σ1. in extensional regime.
2- Volume change during deformation is called ………dilation (volumetric)………. strain.
3- Pull-apart basins exist at the ends of strike-slip faults.
4- …positive ….. flower structure is formed when the overlap area between two
strike-slip faults subjected to transpression deformation.
5- The brittle deformation in the rocks is represented by ………faults and fractures……..
6- The buckling is the folding mechanism in which, the upper surface of the
folded bed is subjected to extension whereas its lower surface subjected to
shortening.
QUESTION 3
Choose the correct answer from the brackets
of Five of the following statements: (20 marks)
a-
The lengthening in
the earth's crust is represented by (folds – normal
faults – reverse faults).
b-
σ3 has a horizontal
attitude during the formation of (reverse fault – normal fault).
c-
The trace of reverse
fault is aligned normal to the trend of (σ3 – σ1 – σ2).
d-
The tensile rock strength is (lower – higher) than the compressive rock
strength.
e-
The (infinitesimal –
incremental - finite)
strain is the measuring of sum of strain from an initial shape to the final
shape.
f-
The (brittle –
ductile) rocks show a wide range of plastic deformation.
QUESTION 1 (Plane rotation): (50 marks)
The attitude of a bed is
324, 32º SW. what is its orientation after it has been rotated at 70º
counterclockwise around a vertical axis
after a faulting phase.
What is the attitude of the bed after this
rotation?
QUESTION 2 (Stress analysis): (50
marks)
Two fault sets mapped in an area, set (A) has an
average trend of N68ºW, 70ºNE and slickenside lineation 26º due to NE. Set (B)
has N04ºW, 82ºSW and their slickenside lineation has 61º, due to SE.
What
are the trends of the stress axes that formed these fault sets?
|