What is TEM?

April 22 2022

TEM stands for Transient Electromagnetic and is sometimes referred to as TDEM (Time-Domain Electromagnetic). It is a measurement technique which responds to electrically conductive materials and can be used to obtain vertical resistivity soundings (similar to VES) by inductive methods. This means that, unlike VES, a physical connection to the ground is not required, with wire loops used for transmitting and receiving signals.

With TEM you measure the resistivity distribution in 1D by inducing a transient current into the ground beneath a transmitter loop. This transient current will create a secondary magnetic field which is recorded by a receiver coil. The recorded response can then be used to create a layered model of the resistivity beneath the equipment.

TEM investigations can reach large depths (>500 m) more simply than VES. Because the method responds positively to conductive bodies, it is mostly used for groundwater prospection and monitoring, studies of saline intrusion and contaminant plumes, and mineral exploration.

What is TEM?

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