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Much of the image consists of blank locations now with little or no radar response. The "yard" wall is still showing strongly, however, and there are continuing tips of a difficult surface in the SE corner. Time piece from 23 to 25ns. This last slice is now almost all blank, but a few of the walls are still showing strongly.

How deep are these pieces? Regrettably, the software I have access to makes approximating the depth a little tricky. If, however, the leading 3 slices represent the ploughsoil, which is most likely about 30cm think, I would guess that each slice is about 10cm and we are just coming down about 80cm in overall.

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Luckily for us, most of the websites we have an interest in lie just below the plough zone, so it'll do! How does this compare to the other methods? Comparison of the Earth Resistance data (top left), the magnetometry (bottom left), the 1517ns time piece (top right) and the 1921ns time piece (bottom left).

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Magnetometry, as talked about above, is a passive method determining regional variations in magnetism against a localised zero value. Magnetic vulnerability study is an active strategy: it is a procedure of how magnetic a sample of sediment could be in the existence of an electromagnetic field. How much soil is checked depends on the size of the test coil: it can be extremely small or it can be reasonably large.

The sensor in this case is extremely little and samples a tiny sample of soil. The Bartington magnetic susceptibility meter with a large "field coil" in use at Verulamium throughout the course in 2013. Top soil will be magnetically enhanced compared to subsoils merely due to natural oxidation and decrease.

By determining magnetic susceptibility at a fairly coarse scale, we can identify locations of human profession and middens. Unfortunately, we do not have access to a reliable mag sus meter, but Jarrod Burks (who assisted teach at the course in 2013) has some excellent examples. Among which is the Wildcat website in Ohio.

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These villages are often laid out around a central open area or plaza, such as this rebuilt example at Sunwatch, Dayton, Ohio. Sunwatch Town, Dayton, Ohio (picture: Jarrod Burks). At the Wildcat website, the magnetometer survey had actually found a range of features and houses. The magnetic vulnerability study helped, nevertheless, define the primary area of occupation and midden which surrounded the more open location.

Jarrod Burks' magnetic vulnerability study arises from the Wildcat website, Ohio. Red is high, blue is low. The method is therefore of excellent use in defining areas of general occupation instead of determining specific functions.

Geophysical surveying is an applied branch of geophysics, which uses seismic, gravitational, magnetic, electrical and electro-magnetic physical methodologies at the Earth's surface area to measure the physical homes of the subsurface - Geophysical Surveys in Beeliar Western Australia 2021. Geophysical surveying techniques usually measure these geophysical properties in addition to anomalies in order to assess different subsurface conditions such as the existence of groundwater, bedrock, minerals, oil and gas, geothermal resources, spaces and cavities, and a lot more.