7. Where we work: A distribution plot of survey locations • Utility Mapping Jobs • Other Jobs (e.g. Forensic) • Archaeology jobs • Engineering Jobs
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12. Magnetic Susceptibility A reconnaissance technique which being rapid and cost effective allows large areas to be surveyed in a very short space of time. Areas can then be targeted with more intensive and higher resolution techniques such as gradiometry and earth resistance. Applications (archaeological): for large rural sites to measure the level of past human activity and inform detail survey.
14. Detailed Magnetic Survey A detailed technique which is still relatively quick and cost effective. The most common technique for locating buried remains in a rural context. Limitations: Strongly affected by magnetic material so can not be used near buildings, fences or in many urban contexts. Applications (archaeological): Locating archaeological features (ditches, pits and other cut features, kilns, hearths etc) on development sites for solar farms, wind farms, housing development etc. Applications (engineering): Locating buried ferrous objects (unexploded ordnance etc).
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16. Earth Resistance A detailed archaeological technique which is ideal for locating buried masonry remains. Not as quick and cost effective as detailed magnetic survey and therefore not as widely used. Limitations: Probes need to be placed into the ground so this technique can not be used over hard surfaces. Applications (archaeological): Locating buried masonry remains (walls, rubble/hardcore, made-ground, roads or trackways) and cut features such as ditches, pits and graves.
17. Survey to locate the foundations of a section of an old manor that had been demolished due to fire damage. Data collected at 0.5m centres
25. Ground Probing Radar (GPR) GPR is often the only geophysical technique that can be used in environmental, engineering and archaeological applications on busy urban and industrial sites. It is capable of working through a wide variety of surface materials both inside and outside buildings and structures. Typical locations can range from car parks, highways and waste ground through to factory floors and basements.
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29. Ground Probing Radar (GPR) As the shape of the electromagnetic pulse is a cone the antenna will actually ‘see’ an object before it crosses it.
30. Ground Probing Radar (GPR) The distance to the object effectively decreases as the antenna gets closer, reaching a minimum when the antenna sits directly above the object.
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32. Ground Probing Radar (GPR) Different frequency antennas can be used for different applications: High frequency antennae have a high resolution, but shallow depth of penetration, whilst low frequency antennas have a lower resolution but can penetrate to much larger depths. 1500MHz antenna 400MHz antenna 200MHz antenna
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