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GPH701S- GEOPHYSICS - 1st Opp - JUNE 2022 |
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NAMIBIA UNIVERSITY
OF SCIENCE AND TECHNOLOGY
FACULTY OF HEALTH, APPLIED SCIENCES AND NATURAL RESOURCES
DEPARTMENT OF NATURAL AND APPLIED SCIENCES
QUALIFICATION: BACHELOR OF SCIENCE
QUALIFICATION CODE: 07BOSC
COURSE CODE: GPH701S
LEVEL: 7
COURSE NAME: GEOPHYSICS
SESSION: JUNE 2022
DURATION: 3 HOURS
PAPER: THEORY
MARKS: 100
EXAMINER (S)
MODERATOR:
FIRST OPPORTUNITY EXAMINATION QUESTION PAPER
MR EMMANUEL EJEMBI
MR ROBERT MWANACHILENGA
INSTRUCTIONS
1. Write all your answers in the answer booklet provided.
2. Read the whole question before answering.
3. Begin each question on a new page.
PERMISSIBLE MATERIALS
Scientific Calculator
THIS QUESTIONS PAPER CONSISTS OF 4 PAGES (Including this front page)
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QUESTION 1
[20]
1.1 Sketch a well labelled diagram of the earth structure, showing the three layers and
(8)
their discontinuity.
1.2 List any four minor tectonic plates.
(2)
1.3 List 4 application of geophysical surveying and their appropriate survey method.
(4)
1.4 Briefly explain the Mantle layer of the earth structure.
(6)
QUESTION 2
[20]
2.1 State the two types of surface waves?
(5)
2.2 What do you understand by the term Bulk modulus (k) of an elastic body?
(5)
2.3 Explain the term dip move Du Ata:
(3)
2.4 The velocity of top layer of a 2-layer model is 1.34 kms? and that of the bottom is
(7)
2.1 kms~}. What are the critical angle of refraction and critical distance X-if depth
h is 31 km.
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QUESTION 3
[15]
3.1 Define seismic velocity.
(2)
3.2 Name the two Newton laws, which the gravity method depends on.
(3)
3.3 What are the sources of seismic noise?
(4)
3.4 Briefly explain the two types of seismic noise.
(6)
QUESTION 4
[15]
4.1 What are the difference between the two kind of gravity meters?
(4)
4.2 Briefly discuss the following gravity corrections.
(6)
4.3 A long horizontal underground tunnel of circular cross section (radius 1m) and
(5)
density 2650kg/m is driven in a rock, if the tunnel produces a max anomaly of
0.01mgal at the surface. Find the depth to its axis (G = 6.670 x 10714Nm?kg~?).
QUESTION 5
[15]
5.1 What did you understand by the term magnetic anomaly.
(2)
5.2 List two oxide of iron and their chemical compositions.
(4)
5.3 With the aid of a concise diagram, briefly explain the working principle of the
(9)
Flux-gate Magnetometer
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QUESTION 6
[15]
6.1 State electric field intensity.
(2)
6.2 What are the difference between electric resistivity and conductivity of a conductor.
(4)
6.3 Sketch an electric circuit showing the four-electrode configuration for a resistivity
(4)
measurement.
6.4 Write down the equation for resistivity in the Werner Configuration and define the
(5)
various parameters.