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GPH701S - GEOPHYSICS - 2ND OPP - JULY 2023 |
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nAmlBIA unlVERSITY
OF SCIEnCE Ano TECHnOLOGY
FACULTY OF HEALTH, NATURAL RESOURCES AND APPLIED SCIENCES
SCHOOL OF NATURAL AND APPLIED SCIENCES
DEPARTMENT OF BIOLOGY, CHEMISTRY AND PHYSICS
QUALIFICATION: BACHELOROF SCIENCE
QUALIFICATION CODE: 07BOSC
LEVEL:7
COURSE CODE: GPH701S
SESSION: JULY2023
DURATION: 3 HOURS
COURSE NAME: GEOPHYSICS
PAPER:THEORY
MARKS: 100
EXAMINER (S)
MODERATOR:
SECOND OPPORTUNITY EXAMINATION QUESTION PAPER
MR EMMANUEL EJEMBI
MR OLUWOLEJACOBOLUWASANMI
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
(15)
1.1 Draw a well labelled diagram of the earth's structure, showing the mechanical
(5)
subdivision, and the continental and oceanic crust.
1.2 What materials are in the continental crust?
(4)
1.3 List any of the four major tectonic plates.
(2)
1.4 Briefly explain the following mechanical subdivisions of the earth.
1.4.1 Asthenosphere
(2)
1.4.2 Siderosphere
(2)
QUESTION 2
2.1 Define seismic velocity.
(20)
(2)
2.2 What are body elastic waves? Briefly outline the Characteristic difference between
(5)
these waves.
2.3 What do you understand by the term dipping angle (oc) of a single horizontal reflection? (5)
2.4. What is the crossover distance for direct and critically refracted rays in the case of an (8)
horizontal interface at a depth of 200 m separating a top layer of velocity 3.0 km/s from a
lower layer of velocity 5.0 km/s
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QUESTION 3
3.1 What do you understand by the term coherent noise?
(15)
(2)
3.2 List 3 sources of seismic noise.
(3)
3.3 Briefly discuss the factors that affect seismic velocities.
(5)
3.4 Briefly explain seismic data arrangement process.
(5)
QUESTION 4
(20)
4.1 State the two Newton laws on which the gravity method depends on.
(4)
4.2 What do you understand by the term curie temperature (TC)?
(3)
4.2 Show that the maximum attraction of a body of mass M is caused at point P as if the
(6)
= - w hoIe mass .Is concentrate d at t he centre .Is g.iven bY 9zmax 4nG-p Rz3z .
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4.4 Calculate the maximum gravity anomaly due to a sphere of radius 1km and a density
(7)
= containing 300 kgm-1 buried at a depth of 15 km (G 6.672 x 10- 11 Nmkg- 2 )
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QUESTION 5
(15)
5.1 Write down the equation for magnetic potential and define the various parameters.
(2)
5.2 List the three varieties of ferromagnetism
(3)
5.3 Differentiate between primary and secondary remanent magnetization.
(4)
5.4 Explain the following terms:
5.4.1 Chemical remanent magnetization (CRM).
(2)
5.4.2 Detrital remanent magnetization (DRM).
(2)
5.4.3 Thermoremanent magnetization (TRM).
(2)
QUESTION 6
(15)
6.1 What equipment is used in electrical resistivity survey?
(2)
6.2 List two important physical properties of rocks required for electrical surveying.
(4)
6.3 Which two characteristic of the ground determines its electrical resistivity?
(4)
6.4 Write down the equation for resistivity in the double-dipole Configuration and define (5)
the various parameters.
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