Magnetotellurics

Magnetotellurics is a method that uses natural electromagnetic currents in the Earth to infer which regions of the subsurface are more conductive or resitive to electric currents.

What can we resolve with MT? These images show a series of simulations of different amounts of electric resistivity beneath a volcano and what real data might be able to determine. (Courtesy: Unsworth)

Real data inversion from Mt. St. Helens (Hill et al., 2010)