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Magnetotellurics

Part of Electromagnetic Methods: Deep EM Extension

Magnetotellurics uses natural electromagnetic fields, from lightning activity and solar-wind interactions, as a free source for deep sounding. Measuring orthogonal electric and magnetic field components yields apparent resistivity and phase as functions of period, and longer periods probe deeper.

Learning Objectives

Undergraduate Core: By the end of this module, you will be able to:

  • Explain how natural electric and magnetic fields form the MT impedance.
  • Calculate apparent resistivity from impedance magnitude and interpret phase qualitatively.
  • Relate period to approximate depth sensitivity without treating it as a hard boundary.
  • Distinguish MT, geomagnetic sounding, marine CSEM, and TEM source–receiver concepts.
Graduate Extension

Evaluate dimensionality, tensor impedance, static shift, distortion, and regularization in 1D versus multidimensional MT inversion.

Practice this module Teach with active-learning slides

Learning Path

Work through the apps in order. Each one opens full screen; the bar at its top shows this path and has Prev and Next buttons.

  1. Deep EM Visualizer Interactive lecture

    Four deep EM methods side by side: geomagnetic sounding, magnetotellurics, marine CSEM, and TEM.

  2. 1D Magnetotelluric Sounding Explorer Demo

    Build a layered-earth model and watch the apparent-resistivity and phase curves respond across the period range.

How the apps connect. The Deep EM Visualizer compares what four deep methods sense; the Sounding Explorer then turns its MT mode into apparent-resistivity and phase curves you can model layer by layer. The Visualizer's TEM mode builds on CW vs. TEM Waveforms and the 1D EM Response Explorer from the Electromagnetic Methods module.

After the path: practice questions · data and notebooks.

Data and Notebooks