18-Geol-A7 Applied Geophysics
Worked solutions to 9 past sittings (2013–2019), 85 questions. Pick a sitting, or start from a topic below.
- December 2019
- December 2018
- May 2018
- December 2017
- December 2016
- May 2015
- December 2014
- May 2013
- Undated paper
Topics across the sittings
Topics that come up in more than one sitting, taken from the headings of our worked solutions. A topic counts once per sitting.
- Processing (6 sittings): December 2019 Q8 · December 2018 Q9 · May 2018 Q3 · December 2017 Q3 · December 2016 Q2 · May 2015 Q3
- Case History (4 sittings): December 2018 Q6 · December 2017 Q4 · May 2015 Q9 · Undated paper Q8
- Electromagnetic Methods (4 sittings): December 2018 Q6 · May 2018 Q6 · December 2016 Q5 · Undated paper Q6
- Electrical (3 sittings): May 2018 Q6 · December 2016 Q5 · Undated paper Q6
- Forward (3 sittings): May 2018 Q10 · December 2017 Q10 · December 2016 Q9
- Gamma-Ray Spectrometry (3 sittings): December 2018 Q3 · May 2018 Q3 · Undated paper Q7
- Interpretation (3 sittings): December 2019 Q3 · December 2018 Q2 · December 2017 Q2
- Seismic Reflection (3 sittings): December 2018 Q10 · December 2016 Q2 · May 2015 Q2
- Three Geophysical Well-Logging Tools (3 sittings): December 2018 Q8 · May 2018 Q8 · December 2017 Q8
- Acquiring (2 sittings): December 2017 Q3 · May 2015 Q3
- Airborne (2 sittings): May 2018 Q9 · December 2016 Q7
- Borehole Electromagnetic Systems (2 sittings): May 2018 Q9 · December 2016 Q7
- Displaying (2 sittings): December 2017 Q7 · May 2015 Q7
- Enhancing Geophysical Data (2 sittings): December 2017 Q7 · May 2015 Q7
- Geometry (2 sittings): December 2019 Q6 · December 2018 Q4
Questions by sitting
December 2019
- Question 1: Physical Properties Sensed by Geophysical Methods — Range and Implications
- Question 2: Designing a Gravity Survey — Target, Setting, Contrast, Signal/Noise and Acquisition
- Question 3: Converting Geophysical Data into an Image — Gridding, Colour/Shading, and Interpretation
- Question 4: Passive and Active Electrical Methods — Field Generation, Measurement and Application
- Question 5: Strengths and Weaknesses of Gamma-Ray Spectrometry
- Question 6: Three Electromagnetic System Configurations — Components, Geometry and Application
- Question 7: Three Downhole Geophysical Tools — Principles and Interpretive Use
- Question 8: Refraction Seismic — Acquisition, Processing, Interpretation and a Case Example
- Question 9: Reflection Seismic Source/Sensor Combinations — Engineering, Petroleum and Marine, and Reaching the Moho
- Question 10: The Magnetotelluric Method — Principles, Equipment and Interpretation
December 2018
- Question 1: Electrical Conductivity — Definition, Typical Values, and Relation to Resistivity and Conductance
- Question 2: Seismic Refraction Over a Low-Velocity Layer — Ray Paths, Snell's Law and Interpretation
- Question 3: Gamma-Ray Spectrometry — Radiation Types, the U-238 Decay Chain, and a Disequilibrium Discrepancy
- Question 4: Resistivity Array Configuration — Geometry, Apparent Resistivity, and Survey Processing
- Question 5: Ferromagnetism, Antiferromagnetism and Ferrimagnetism; Induced vs. Remanent Magnetization
- Question 6: The Electromagnetic Method — Governing Physics, Transmitter/Receiver Operation and a Case History
- Question 7: Gravity Surveying — Instrumentation, Data Reduction, and a Case History
- Question 8: Three Geophysical Well-Logging Tools
- Question 9: The Magnetotelluric Method — Data Collection, Processing and a Case History
- Question 10: Seismic Reflection — Source Gather Geometry, Multi-Layer Arrivals and Multiple Suppression
May 2018
- Question 1: Magnetic Susceptibility and Remanence
- Question 2: Seismic Reflection Acquisition Geometry and Zero-Offset Section Generation
- Question 3: Gamma-Ray Spectrometry — Applications, Survey Design and Processing
- Question 4: Downhole Resistivity Survey Arrays
- Question 5: Time-Domain vs. Frequency-Domain Geophysical Measurements
- Question 6: Electrical vs. Electromagnetic Methods
- Question 7: High-Pass vs. Low-Pass Filtering of Geophysical Data
- Question 8: Three Geophysical Well-Logging Tools
- Question 9: Airborne, Ground and Borehole Electromagnetic Systems
- Question 10: Forward and Inverse Modelling in Quantitative Geophysical Interpretation
December 2017
- Question 1: Density — Values, Gravity Contrast, and Seismic Velocity/Reflectivity
- Question 2: Seismic Refraction Survey Design, Execution and Interpretation
- Question 3: Planning, Acquiring, Processing and Interpreting a Magnetotelluric (MT) Survey
- Question 4: Resistivity Survey Arrays — Configuration, Strengths/Weaknesses, and a Case History
- Question 5: Chargeability — Mechanisms, Measurement, and a Case History
- Question 6: Magnetic Anomaly Dependence on Magnetic Latitude and Reduction Methods
- Question 7: Displaying and Enhancing Geophysical Data
- Question 8: Three Geophysical Well-Logging Tools
- Question 9: An Electromagnetic (EM) System in Detail
- Question 10: Forward and Inverse Modelling in Quantitative Geophysical Interpretation
December 2016
- Question 1: Planning a Geophysical Survey
- Question 2: Seismic Reflection — Physical Properties, Application and Processing
- Question 3: Three Well-Logging Tools
- Question 4: Gamma-Ray Spectrometry Surveys
- Question 5: Electrical vs. Electromagnetic Methods
- Question 6: The Fourier Transform in Geophysical Data Processing
- Question 7: Airborne, Ground and Borehole Electromagnetic Systems
- Question 8: Enhancing Features in Geophysical Data
- Question 9: Forward and Inverse Modelling
- Question 10: Geophysical Techniques for a Chosen Application — Groundwater
May 2015
- Question 1: Physical Properties in Applied Geophysics
- Question 2: Seismic Reflection vs. Refraction Surveys
- Question 3: Planning, Acquiring, Processing and Interpreting a Magnetotelluric Survey
- Question 4: Geophysics in Oil and Gas Exploration
- Question 5: Time-Domain vs. Frequency-Domain Geophysical Instruments
- Question 6: Magnetic Anomaly Variation with Latitude and Reduction Methods
- Question 7: Displaying and Enhancing Geophysical Data
- Question 8: Geophysical Well-Logging Tools
- Question 9: The Geophysical Project Workflow – A Case History
December 2014
- Question 1: Short Answers Across Methods
- Question 2: Gravity Terrain Corrections, Nettleton's Method, Magnetic Anomaly Comparison
- Question 3: Sphere Anomaly Components and Rock Magnetism
- Question 4: Electrical Polarization Mechanisms and IP Measurement
- Question 5: HLEM Traverse Over a Conductive Sheet
- Question 6: CMP Gather – Normal Moveout and the Dix Equation
- Question 7: Resistivity Sounding, Pseudo-sections and Inversion
- Question 8: Reversed Refraction Profile – Dipping Interface
May 2013
- Question 1: Geophysical Terms
- Question 2: Method Selection for Five Applications
- Question 3: Airborne Radiometrics and a Gamma-Ray Spectrum
- Question 4: Time-Domain EM — Large-Loop Transmitter and Plate Response
- Question 5: Detecting a Thin Middle Layer — Three Methods, and the Equivalence Principle
- Question 6: Magnetic Anomaly Interpretation and Instrument Comparison
- Question 7: Gravity Survey Over a Suspected Tunnel — Horizontal Cylinder Model
- Question 8: Seismic Refraction — Apparent Velocities, Earth Models and Depth to Bedrock
Undated paper
- Question 1: Physical Properties Sensed by the Major Geophysical Methods
- Question 2: The Gravity Method — Physical Laws, Instrumentation and Corrections
- Question 3: Subsurface (Borehole) Geophysical Studies
- Question 4: Geophysical Surveys Across Multiple Scales and Project Stages
- Question 5: The Magnetic Method for Reconnaissance, Property-Scale and Borehole Surveys
- Question 6: Electrical vs. Electromagnetic Methods
- Question 7: Gamma-Ray Spectrometry
- Question 8: Seismic Refraction — Survey Design, Case History and Noise
- Question 9: Acoustic Impedance and the Role of Sonic Logs in Reflection Seismic
- Question 10: Case History — the Seismic Reflection Method