Structural geology is the study of rock structures like folds, faults, and joints that result from movements and deformation of the earth's crust. Geological structures provide evidence of crustal deformation caused by tectonic forces, which can also cause earthquakes. Folds, faults, and joints are the main types of structures that develop in rock formations due to different tectonic processes. Folds involve bending of rock layers, faults involve displacement of adjacent blocks, and joints are fractures without displacement. These structures are important to civil engineering projects and can impact groundwater flow, tunneling, landslides, reservoir leakage, and more.

1. ENGINEERING GEOLOGY
UNIT: 1 INTRODUCTION & WEATHERING OF ROCKS
IMPORTANCE OF STRUCTURAL GEOLOGY Y
Dr G SUBBARAO
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2. Structural Geology
is the study of rock
structures such as
folds, faults, joints
etc that have
resulted from
movements and
deformation of the
earth’s crust
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3. Geological structures are the evidences of
crustal deformation (changing earths surface caused
by tectonic forces and then cause for earthquakes)
Depending on the process involved,
the following various types of structures
develop in the geological formations
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4. Folds
Folds are one of the most common
geological structures found in rocks
Folds are best displayed by stratified
formations such as sedimentary or their
metamorphosed equivalents
Folds can be seen in Granitic gneiss, iron
formations, limestones, shales, slates etc8/29/2020 4

5. ANTICLINE – SYNCLINE SYNCLINAL FOLD
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6. Faults may be described as
fractures along which
relative displacement of
adjacent blocks takes place
The relative displacement
caused during faulting may
be horizontal, vertical and
inclined
FAULTS
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7. Some faults are only a few
inches long, and the total
displacement is measured
in fractions of an inch
while there are faults that
are hundreds of miles long
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8. When formations are
subjected to stress,
the deformation in the
development of fractures in a
rock along which there has
been an observable amount of
displacement can be seen
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9. The magnitude of fault obviously depends on
the intensity and the nature of
shearing stress involved
(various tectonic forces)
Occurrence of fault is often accompanied
by earthquakes and it is an indication of
subsurface instability of the
region concerned
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10. Joints are fractures or openings in the rock
formations
These differ from the faults in that there is no
displacement along them
JOINTS
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11. Most of the joints are formed due to
either tensional or shearing forces and
accordingly, they are described as
tension or shear joints respectively.
Naturally, the presence of joints divides the
rock into a number of parts or blocks
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12. Importance of joints from civil engg point of view
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13. Joints may pose groundwater problems in tunneling.
Large joints cause landslides
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14. Joints cause the leakage of water in case of reservoir.
Mineral exploration in mining sector becomes easy due to the presence of
joints.
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15. Presence of joints in rocks allow the movement of water and may act as
Aquifers
Bore wells drilled in civil construction areas for water supply will be
more productive in highly jointed rocks than in less jointed rocks
The orientation of joints is very significant in engineering projects
Quarry operations obviously influenced by the joints
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16. Thank you
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17. 1. The study of rock structures such as folds, faults, joints is called as ___
2. Folds can be seen in GNEISS, SHALES, SCHIST, LIMESTONE, SLATES
3. A fold ie convex upward and the two limbs dip away from each other is known as ______
4. A fold ie convex downwards and the two limbs dip toward each other is known as ________
5. Faults occur due to _____
6. Occurrence of fault is always accompanied by ________
7. ______ are fractures / openings in the rock formations
8. Joints may pose groundwater problems in_______
9. joints cause ______________
10. Presence of joints in rocks allow the movement of water and may act as _____
1.4 importance of structural geology
ASSIGNMENT 2
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18. 1. Structural Geology
2. True
3. Anticline
4. syncline
5. Compressional stress, Tensional stress
6. earthquakes
7. joints
8. tunneling
9. landslides
10. aquifers
ANSWERS
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