Magnetic Methods
Rocks acquire magnetization from magnetic minerals, magnetite above all, and that magnetization perturbs the geomagnetic field measured at the surface. Because the inducing field is inclined, magnetic anomalies change shape with latitude, which makes interpretation richer than gravity even though the survey practice is faster.
Learning Objectives
Undergraduate Core: By the end of this module, you will be able to:
- Distinguish induced magnetization, remanent magnetization, and magnetic susceptibility.
- Predict how inclination, source depth, and observation height affect anomaly shape.
- Explain upward continuation, simple depth rules, and reduction to the pole (RTP).
- Identify when cultural noise or remanence makes a simple interpretation unreliable.
Graduate Extension
Assess the assumptions and instability of continuation, RTP, and source-depth estimators, especially at low inclination and for remanently magnetized bodies.
Practice this module Teach with active-learning slides
Interactive Lecture
-
🖥️ Virtual Rock Magnetism Lab & Activity
Susceptibility, remanence, and how rock types differ as magnetic sources.
Topic Apps
-
🖥️ Interactive Geomagnetic Anomaly Simulator
How buried magnetic bodies express themselves in total-field data.
-
Upward and downward continuation as wavelength filtering of a field map.
-
🖥️ Magnetic Anomaly Interpretation Methods
Depth rules and shape analysis for practical anomaly interpretation.
Demo
-
⚡ Dipole Anomaly vs. Inclination Explorer
Move the same buried dipole from the magnetic equator to the pole and watch the anomaly change from asymmetric to symmetric.
Classroom Lab
🧰 Concealed dyke and buried-vessel profiles — interpolate a base station, remove diurnal and regional fields, compare total-field and gradient data, and frame a safe target recommendation.