Time-Domain EM (TDEM) is a geophysical technique in which electric and magnetic (EM) fields are induced by transient pulses of electric current generated by a loop of wire or coil and the subsequent decay response is measured by a receiver coil. These secondary EM fields are recorded as the induced energy diffuses deeper into the earth. The rate of diffusion indicates the resistivity of the subsurface materials and is quantified by measuring the change in amplitude of this EM field at a number of fixed times or channels which are measured as changes in voltages. TDEM offers an efficient way to map conductivity at depth with high spatial resolution as cross-sections are generated in a fraction of the cost and time compared to more traditional methods. Most common applications include environmental, groundwater, and mineral exploration.