TTEM surveys
Bargheer Geophysics conducts onshore and offshore TTEM surveys at a competitive price with no outlay for equipment or processing software from a supplier.
We are highly experienced in the full range TEM family of methods: on land (TTEM), water (FloaTEM) and their operation in all conditions: from the searing heat of the desert to the biting cold of the Polar regions – and everything in between.
Basic principles
TEM (Transient electromagnetics) measures the response of the underground to pulses of electric current. Various configurations can be used according to the objects of interest, their depth below the ground surface, and the situation in the field.
In the field
Frequently, the instrument is towed over an area, hence the acronym TTEM, or towed TEM. On land, an ATV (quad bike) can be used to tow the instrument over the survey area in order to rapidly capture large amounts of data per field day. On water the procedure is similar, except that the instrument is towed over the surface of the water on a boat or raft. The continuous data generated is processed to create a series of profiles, providing an overview of what lies below.
Depth of surveys can be targeted at the subsurface (1-2m) down to around 200m. Generally speaking, deeper surveys come at the cost of resolution in the upper layers.
We are happy to advise on the best way forward to ensure the use of the most appropriate configuration for your specific requirements, as the vast array of products and services offered elsewhere can seem overwhelming to the non-specialist. We help to separate the wheat from the chaff, allowing you to make the right decision for your survey.
Applications
- Groundwater surveys assessing the availability and quality of drinking water.
- Mapping the volume and extent of overlying clay layers protecting aquifers.
- Mapping the possible spread of pollution in the underground.
- Determining saltwater intrusion in coastal areas.
- Detection of fracture zones within the underlying bedrock. These are important to understand in order to determine how water permeates underground and where is likely to be found in abundance.
- Affects the siting of wells and the identification of areas where water can be pumped into aquifers as part of managed aquifer recharge.
- Study of throughflow patterns, including hydrogeology below bodies of surface water.
- Investigation of underlying geology.
- Prior to major construction works (e.g. major roads, large buildings) in order to determine materials and methods to be used.
- For mineral exploration.
- Permafrost mapping (as a supplement to Ground Penetrating Radar – GPR).
- To supplement or replace other types of geophysics when this is the right tool for the job.