• These are important to Civil Engineers due to its implications on the construction of infrastructure projects

• Shown below are the different types of geological maps

• Crust the outermost layer consisting mostly of basalt and granite, and is subdivided into two types: Oceanic (denser & thinner) and Continental (less dense)

• Mantle lies below the crust with thickness range up to 2900 km. The crust together with the upper part of the mantle comprise the lithosphere, which is divided into two plates, both large and small.

• The core is made of two parts, liquid outer core and solid inner core.

• These are rocks deforming plastically under compressive stresses. They do not return to their original shape.There are four types of folds, which includes monocline, anticline, syncline, and plunging folds. Folds can be classified by their geometry with respect to their axial plane. These are Symmetrical folds, Asymmetrical folds, and Overturned folds. Thus, the greater asymmetry in the fold, the more intense the deformation.

• A joint is a crack in the rock along which no appreciable movement has occurred. Strata on the side of the joint align with strata on the other side. Joints can form as a result of expansion and contraction of rocks. Additionally, joints aid in weathering by providing channels where water and air can reach deep into the formation.

• A fault is a plane of dislocation where rocks on the side of the fault have moved relative to rocks on the other side. Strata on one side of the fault plane are typically offset from strata on the opposite side. Faults can form in response to three types of forces such as tension, compression, and shear.

1.Location of tunnels – Folded rocks are greatly strained, their removal for tunneling can cause rock explosions. Along the crests of folds, the rocks are in tension, therefore highly unstable. Along the troughs, rocks are highly compressed, hence tough, offer greater resistance to excavation for tunneling. Tunneling can be done along the limbs

2.Quarrying – It should be done along the limbs, since there is better quality of rocks available. Fractures associated with crests and troughs are absent along limbs. Seepage problems along crests and troughs can be avoided

3.Groundwater occurrence – Synclines often furnish excellent conditions to tap ground water. Artesian wells and springs originate from synclines. Fractures present in folded strata act as channels for ground water movement

4. Laying Roads and Railway tracks along hill slopes – Ground stability depends on the mutual relation of the dip of the beds and the slope of the cutting. If the surface slope and the dip are in opposite direction, the ground is stable. If the surface slope and the dip collide, the ground is unstable.

5. Oil, Gas and Ore deposits – Oil, Gas, and Ore deposits are often associated with anticlines. Suitable cap rocks, are also an essential requirement. Crests of folds offer convenient places for the occurrence of ore deposits.

1. Location of dams and reservoirs – Too many joints in a site, will render it unstable for construction of dams. They act as avenues for serious leakage of water. Upstream dipping joints are less harmful

2. Occurrence of Landslides – Landslides take place, when the surface slope of the hills and the dip of the beds are in the same direction. Joints facilitate the heavy percolation of water. This water comes in contact with clayey material below the ground, producing fine lubricating materials, which causes the slipping of overlying rocks.

3. Quarrying – Depending on conditions, joints can play a helpful or harmful role in quarrying. Joints cut in situ rocks, which can be easily extracted without the use of explosives. Too many joints, on the other hand, render quarrying useless, due to excessive decay of rocks.

4. Tunneling – Joints can severely hamper the strength of rocks. They may cause rocks to fall from the roof of the tunnel. Joints can cause the ground to be saturated with water, decreasing the strength of the rocks. They may act as sites for the development of solution cavities in limestone terrain

4. Limestone terrain – Faults cause leakage of water, if present in the reservoir basin. Downstream dipping faults cause excess uplift pressure. Fault zone occurring in the upstream of river leads to erosion and accelerated reservoir silting.

1. Location of tunnels – Fault zones, being heavily fractured, makes tunneling unstable. Groundwater associated problems are likely to occur. Renewed faulting can lead to ground displacement.

2. Quarrying – Quarrying the fault zones produce inferior materials, quantitatively and qualitatively

3.Roads and Railway tracks along slopes – Fault zones are highly undesirable for construction of roads and railway, due to the possibility of landslides

4. Groundwater occurrence – Fault zones, being heavily fractured, provides space for storage of groundwater and permits their movement

5. Ore Minerals – Fault zones are often rich in minerals. They favor different process that eventually lead to mineral formation

1. Mineralogical Composition - Rocks are made up of smaller units of minerals. Their properties depend upon the nature and composition of these minerals

2. Texture- It defines the size, shape, and mutual relationship of mineral compounds in a rock.

3. Structure - It determines the movement of large scale features of the rock mass as a whole.

4. Specific Gravity - It is the ratio of the density of solids to water density.

5. Unit Weight - It is the weight per unit volume of a material.

6. Density - It refers to the measure of mass per unit volume. Density of rock material varies and often related to the rock's porosty.

7. Porosity - It describes how densely the material is packed. It is the ratio of non-solid volume (Vv) to the total volume (V) of material.

8. Moisture Content - It is the ratio of the weight of water in the voids to the weight of dry solids in the rock sample.

9. Degree of Saturation - It is the volume of water in the void to the volume of voids in the rock sample.

10. Permeability - It is the ability of porous material to allow liquid to pass through its pores.

11. Electrical Properties - Most rocks are dielectric in nature and measurement of dielectric constants is used for data interpretation.

12. Thermal Properties - Increase in temperature makes rock weaker due to the formation of cracks in the rockmass.

13. Swelling - It is the increase in volume of the mass due to suction of water due to contact of water for a long time.

14. Anisotropy - Properties of the elements of rock mass are not similar in every direction, due to sequence of rock formation (existence of bedding planes, etc.)

15. Durability - It refers to the rock's resistance to destruction.

1. Compressive Strength - It is the measure of the ability of material to resist uniaxial compressive loads without yielding or fracture. The most common measure of compressive strength is the uniaxial compressive strength or unconfined compressive strength

2. Tensile Strength - It is defined as the maximum tensile stress which a material is capable of developing

3. Shear Strength - It is defined as the maximum resistance to a deformation due to shear displacement caused by shear stress. Shear strength in a rockmass is derived from the surface frictional resistance along the sliding plane, interlocking between individual rock gains and cohesion in sliding surface of the rock

• P in P waves stands for primary, because these are the fastest seismic waves and are the first to be detected once an earthquake has occurred.

• P-waves travel through materials with rigidity and/or compressibility and density.

greater rigidity = faster P-waves

greater compressibility = faster P-waves

greater density = slower P-waves

• P-wave velocity increases with mafic mineral content, curve, and pressure and decreases with temperature.

• The S in S-waves stands for secondary, because they are the second-fastest seismic waves and the second type to be detected once an earthquake has occurred.

• S-waves travel through materials with rigidity and density.

greater rigidity = faster S-waves

greater density = slower S-waves

• S-wave velocity increases with mafic mineral content and pressure, and decreases with presence of fluid such as porous sand or patial melt

• Surface waves are typically generated when the source of an earthquake is close to the Earth's surface. As their name suggests, surface waves travel just below the surface of the ground.

• Rayleigh waves are set off by the combined effect of P- and S- waves on the earth's surface. People who are outdoors during a major earthquake commonly see Rayleigh waves moving across the surface of the Earth, and can feel the ground rising and falling as the waves pass beneath them.

• Love waves involve the surface shearing sideways and then returning to its original form as each wave passes. All surface waves travel slower than body waves and Rayleigh waves are slower than Love waves.

a.) Cement Grouting - – Cement (or cementitious grout) is used for high-permeability ground wherein neat cement and water or a mixture of sand (4 parts) to cement (1 part) is the usual composition .

b.) Bentonite Grouting – This is used where soil particles are too small for cement grouting, most commonly to combat seepage in alluvial soils beneath the foundations of dams or water bound structures.

c.) Chemical Grouting - Chemical grouting is used in soils of medium to coarse-grading. Materials such as sodium silicate and calcium chloride are mixed together in liquid form and solidified into a gel.

d.) Resin Grouting - Resin grouts have a very low viscosity and are able to penetrate fine sands.

e.) Bituminous Grouting - Bitumen emulsion can serve as a suitable grouting material that can be injected into fine sands as an impermeable barrier to water. Soil strength will not be increased, but cut-off walls beneath dams and other water-bound structures can be formed effectively.