A master course that I taught at ETH Zurich for students specializing in Earth, Environmental, and Planetary sciences.

Summary

The course guides students in learning about electromagnetic induction in the Earth and surrounding space. It focuses on analyzing and interpreting time-varying EM fields observed at Earth's surface, seafloor, and satellites. These fields are used to image electrical conductivity distributions in Earth's interior and forecast space weather hazards.

Objectives

• Development of the geophysical and mathematical tools needed to understand electromagnetic induction through the analysis of Maxwell's equations.

• Acquisition of knowledge concerning the physical nature of the magnetospheric, ionospheric, and ocean-induced electromagnetic induction signals.

• Basics of the data interpretation and applications in crust-mantle studies, geothermal exploration, and geomagnetic storm modeling.

Content

• Introduction to electromagnetic induction: governing equations, a summary of the main EM sounding methods.

• Electrical conductivity of rocks and minerals: conduction mechanisms, anisotropy

• Basics of geomagnetic deep sounding (GDS) method: solution of Maxwell’s equations in spherical geometry

• Basics of magnetotelluric (MT) method: solution of Maxwell’s equations in Cartesian geometry, concept of transfer functions, Earth’s impedance tensor

• Motional induction: tidal magnetic signals, satellite observations

• Data acquisition and processing

• Solution of Maxwell's equations in Earth's models with 3-D conductivity distribution.

• Basics of inverse problems. Adjoint method for large-scale inverse problems

• Applications: geothermal exploration, mantle conductivity studies, space weather modeling