IAG Exercises

Introduction


These exercises have been used in undergraduate geophysics courses at UBC. Some are suitable for non-geophysics earth science students, others are appropriate for specialists in geophysics at the senior undergraduate level. The introduction for each explains objectives and the target audience.

Active learning is important. Compared to simply reading, learning is much more effective when actively engaged with the subject. These exercises have been developed with active pedagogy in mind. Some can be done alone, others are best tackled in a group or team-based setting. For all, the goal is to become more proficient at using inversion to solve practical geological and geotechnical problems using geophysics. Some exercises were developed with support from a BCcampus Online Learning Resource grant, and these are licensed under a Creative Commons License. Unless this is explicitely stated on the exercise's front page, all other material is copyright protected, as noted on the IAG front page.
 

Exercise descriptions


All exercises require installation of relevant modelling and inversion codes (dcip2d, or mag3d or grav3d). See Chapter 10, Software & manuals, section a. Outline & installation.

  1. Intro to all exercises - You are here.
  2. 2D DC/IP: forward & inversion - Suitable for first time users to provide insight about how inversion results correspond to the real earth. Forward modelling and inversion using simple 2D synthetic models.
  3. 2D DC: Using inversion - Suitable for first time users to practice using the seven-step framework and 2D inversions. The exercise involves interpreting a small 2D DC resistivity data set in the context of a specific (real) geotechnical goal.
  4. 3D MAGNETICS: forward & inversion - Suitable for first time users who have been introduced to magnetic surveys. Forward modelling and inversion using simple 3D synthetic models provides insight about how inversion results correspond to the real earth.
  5. 3D GRAVITY: forward & inversion - Suitable for first time users who have had an introduction to inversion theory. Forward modelling and inversion of a 3D synthetic model, and inversion of an "unknown" data set.
  6. 2D DC/IP: Application Part I - Mineral exploration exercise: the "setup" and forward modelling components. Tasks include inspecting raw data and gaining initial impressions about the information in these two data sets. Use of forward modelling to build synthetic data sets, then inverting them to gain some reasonable expectations.
  7. 2D DC/IP: Application Part II - Mineral exploration exercise: the processing, inversion and interpretation components. Tasks include inverting 2D resistivity and IP data, characterizing the depth of investigation, use of both DC and IP results to describe the likely geology under the survey line, and applying new skills to carry out inversion and interpretation of a new resistivity data set.
  8. 3D MAGNETICS: Using inversion - Practice interpreting magnetic data, including maps and a simple line profile, but the emphasis is on 3D inversions of a (real) 3D magnetics data set.
  9. Magnetic dipole applet - Exploring the magnetic response to a buried magnetic dipole using a Java Applet.
  10. Applied Geophysics 454 - Exercises for a 13 week course about applied geophysics, taken by undergraduate and graduate students of geophysics.
    1. Exercise 1: Introduction to gravity. Analytic modelling, 3D forward modelling, Data Reduction, No Inversion. Exploring the gravity response to a sphere and prism, and reduction of raw gravity data. 
      Codes Used: MATLAB or a SPREADSHEET, MESHTOOLS and GM-DATA-VIEWER, GRAV3D for forward modelling.
    2. Exercise 2: Gravity inversion. Familiarization with 3D inversion, then invert / interpret real data 3D gravity inversion: explore inversion using synthetic model, then invert San Nicolas data and interpret. 
      Codes Used: MESHTOOLS and GM-DATA-VIEWER, GRAV3D (and optionally MATLAB) .
    3. Exercise 3: Magnetics. Compare dipole and prism responses, invert synthetics, then invert / interpret San Nicolas magnetics data. 
      Codes Used: the MAGNETIC DIPOLE JAVA APPLET, MESHTOOLS and GM-DATA-VIEWER, MAG3D.
    4. Exercise 4: Frequency domain data processing. ALL MATLAB: Fourier processing of potential fields data. These exercises are not related to any content on this CD-ROM.
    5. Exercise 5: DC resistivity #1. Introduction to DC resistivity profiling data, forward modelling of pseudosection data for a synthetic 2D model, introduction to 2D inversion of DC resistivity data.
      Codes Used: DCIP2D and DC/IP UTILITIES.
    6. Exercise 6: DC resistivity #2. Carrying out and using 2D inversions of DC resistivity and IP data.
      Codes Used: DCIP2D and DC/IP UTILITIES.
    7. Exercise 7: Frequency domain EM. This exercise is unrelated to content on this CD-ROM. It may appear on a future version of IAG.