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Nigeria's free digital learning hub. Videos, lecture notes, practice questions and leaderboards aligned with CCMAS, NBTE, NCCE, WAEC, NECO, IJMB and JAMB curricula.
Geology · 300 Level
This is the complete lecture note for GEY 308 Principle of Geophysics, prepared for Geology students at 300 Level. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS GEY 308: Principles of Geophysics (2 Units C: LH 30) Course Code: GEY 308 Course Title: Principles of Geophysics Course Unit: 2 Units C Series 1: Nature And Scope Of Geophysics Series 2: Principles And Techniques Of Geophysical Prospecting Series 3: Gravity, Electrical, Seismic And Electromagnetic Methods Series 4: Introduction To Geophysical Well Logging Series 5: Applications Of Geophysics In Exploration And Environmental Studies Series 1 Nature And Scope Of Geophysics Part 1: The Nature Of Geophysics • 1.1.1 Definition and meaning of geophysics • 1.1.2 Relationship between geophysics and geology Part 2: Scope Of Geophysics • 1.2.1 Major branches of geophysics • 1.2.2 Areas of application in Earth sciences Part 3: Role Of Geophysics In Prospecting And Exploration • 1.3.1 Contribution to mineral, hydrocarbon, and groundwater exploration • 1.3.2 Importance in engineering and environmental studies Introduction Geophysics is a discipline that applies the principles of physics to study the Earth. By examining physical properties such as gravity, magnetism, and seismic waves, geophysics provides insights into the structure and processes of the Earth that cannot be observed directly. This makes it a vital tool in both academic research and practical exploration.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS The aim of this Series is to introduce you to the nature and scope of geophysics, and to highlight its role in geological prospecting and exploration. We shall commence this Series by defining geophysics and examining its relationship with geology. Next, we will explore the scope of geophysics, considering its major branches and areas of application. Finally, we will conclude by discussing the role of geophysics in prospecting and exploration, with emphasis on its contributions to resource discovery and environmental studies. Series Learning Outcomes Upon completing this Series, you should be able to: • SLO 1.1 define geophysics and explain its relationship with geology, • SLO 1.2 describe the major branches of geophysics and their scope, • SLO 1.3 analyse the role of geophysics in mineral, hydrocarbon, and groundwater exploration, • SLO 1.4 evaluate the importance of geophysics in engineering and environmental studies. 1.1 The Nature Of Geophysics 1.1.1 Definition and meaning of geophysics Geophysics is the branch of Earth science that applies the principles of physics to study the Earth. It investigates the physical properties of the Earth, such as gravity, magnetism, heat flow, and seismic waves, to understand its structure and processes. Unlike geology, which often relies on direct observation of rocks and minerals, geophysics provides indirect methods that allow us to explore beneath the surface without excavation. Geophysics is therefore essential for studying areas that are inaccessible, such as deep subsurface layers or large regions covered by soil and vegetation.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.1 Geophysics as the application of physics to Earth studies Fill in the blank: The branch of Earth science that applies the principles of physics to study the Earth is called ______. 1.1.2 Relationship between geophysics and geology Geophysics and geology are closely related disciplines. Geology is the study of the Earth’s materials, structures, and history, often through direct observation and sampling. Geophysics complements geology by providing indirect methods to investigate subsurface features. For example, while a geologist may describe rock outcrops, a geophysicist can use seismic waves to map structures deep underground. This relationship is important because geophysics often confirms or extends geological interpretations. Together, they provide a more complete understanding of the Earth, combining surface observations with subsurface insights.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Plate 1.2 Geology and geophysics as complementary disciplines Fill in the blank: While geology often relies on direct observation of rocks, geophysics uses ______ methods to investigate subsurface features. Pilot questions 1.1 1. Define geophysics in simple terms. 2. What physical properties of the Earth are studied in geophysics? 3. Why is geophysics important for studying inaccessible areas? 4. How does geology differ from geophysics in its approach? 5. Give one example of how geophysics complements geological studies. 1.2 Scope Of Geophysics 1.2.1 Major branches of geophysics Geophysics is a broad discipline with several branches, each focusing on different physical properties of the Earth. Seismology studies seismic waves to understand Earth’s internal structure and to monitor earthquakes. Gravity studies measure variations in the Earth’s gravitational field to detect subsurface density differences. Magnetism investigates the Earth’s
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS magnetic field and its anomalies, which can reveal hidden rock formations. Electrical and electromagnetic methods explore subsurface conductivity, often used in groundwater and mineral exploration. These branches collectively provide tools for investigating both shallow and deep structures of the Earth. Figure 1.3 Major branches of geophysics Fill in the blank: The study of seismic waves to understand Earth’s internal structure is called ______. 1.2.2 Areas of application in Earth sciences Geophysics has wide applications across Earth sciences. In mineral exploration, it helps locate ore deposits by detecting anomalies in gravity, magnetism, or conductivity. In hydrocarbon exploration, seismic surveys are used to identify oil and gas reservoirs. In groundwater studies, electrical methods can map aquifers and water-bearing formations. Beyond resource exploration, geophysics is also applied in environmental studies, such as monitoring pollution or assessing landfill sites, and in engineering projects, where it helps evaluate ground stability before construction.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Plate 1.4 Applications of geophysics in Earth sciences Fill in the blank: Electrical methods in geophysics are often used to map underground ______ formations. Pilot questions 1.2 1. Name two major branches of geophysics. 2. What does seismology study? 3. Which geophysical method is commonly used in groundwater exploration? 4. Give one application of geophysics in environmental studies. 5. Why is geophysics important in engineering projects? 1.3 Role Of Geophysics In Prospecting And Exploration 1.3.1 Contribution to mineral, hydrocarbon, and groundwater exploration Geophysics plays a central role in locating and evaluating natural resources. In mineral exploration, gravity and magnetic surveys are used to detect ore bodies by identifying anomalies in the Earth’s field. In hydrocarbon exploration, seismic methods are employed to map subsurface structures that may trap oil and gas. For groundwater exploration, electrical and electromagnetic techniques help identify aquifers and water-bearing formations. These methods provide indirect but highly reliable information, reducing the need for costly drilling and increasing the chances of successful resource discovery.
LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.5 Geophysical contributions to resource exploration Fill in the blank: Seismic methods are commonly used in ______ exploration to map subsurface structures. 1.3.2 Importance in engineering and environmental studies Beyond resource exploration, geophysics is vital in engineering projects and environmental studies. In engineering, geophysical surveys assess ground stability, detect faults, and evaluate subsurface conditions before construction of dams, tunnels, or buildings. In environmental studies, geophysics helps monitor pollution, investigate landfill sites, and assess contamination in soil and groundwater. By providing non-invasive methods of investigation, geophysics ensures that both engineering and environmental decisions are based on accurate subsurface information.
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