Monday, 16 February 2015

5 Fun facts about geophysics

So I've recently had a few questions about archaeological geophysics (or geofizz in Time Team speak) and what it's like to be a geophysicist. So (without trying to break any confidentiality agreements between myself and commercial clients), here are 5 fun facts that you probably didn't know about geophysics! Some of these are more personal observations, some of which my colleagues and peers will agree with, others they won't.

1. As part of the planning process in Britain (where new developments such as roads, buildings and other such things are included), archaeological geophysics makes its money by obtaining data large areas of ground quickly. By not destroying the archaeology(buried walls, ditches, metallic objects, burnt surfaces, etc.) it involves a fraction of time and money compared to excavation. This also allows us to continue preserving archaeology in the ground rather than in a storage facility, which is a major issue (see here for more info on storage of artefacts). For magnetometry (the most common survey method) this also relies on modern metallic features (such as metallic gates, fences, clothing on the user, etc.) being eliminated from the survey area as much as reasonably possible!

No Arnie, you can't do magnetometry because you're completely made of metal (presumably magnetic).

2. Archaeology is protected by differing levels of protection in the UK, depending on their significance. This also affects who and what can do archaeological fieldwork on certain sites. Scheduled Ancient Monuments (or SAMs, for example Stonehenge) have the most legal protection, while English Heritage has categories for "listed buildings", which has 3 levels of non-statutory protection, from I (the most important) to II* and II. SAMs require legal permissions to survey the land, not just the consent of the landowner, which is always requried for any sort of fieldwork. Normally becuase geophysics is a non-destructive technique, it is not a problem to obtain what is known as a section 42 licence. 

These categories reflect the significance of the archaeology and can relate to any building or open space such as a park. However these are non-statutory, although it doesn't mean you can simply bulldoze all these buildings (not least because many have fascinating histories and often are national treasures in themselves, such as Catesby house, where the gunpowder plot was organised (see here). Other protection (statutory or otherwise) includes listed gardens and parks (including large areas around villages with historic and prehistoric significance, including Ashby St.Ledgers), World Heritage Sites (which are listed by UNESCO, not the British Government, although the sites tend to be run by charities or governments). If the listed area has an open space that isn't overlain by modern human activity then the chances are that you can survey it and detect the archaeology underneath.

Google maps is a great tool but sometimes the labels can be a bit unhelpful... this is a map of all of the scheduled monuments in the UK(!) (taken from

3. Geophysics is the closest thing we can get to creating a 3-D model of archaeology preserved under the ground! We use software to recreate models using the data from ground penetrating radar (GPR), which then can be shown off, such as this video below (courtesy of GSB Prospection ltd.). It would be possible to do this with other geophysical methods like resistivity (electrical resistance) data, if you could obtain depth and had the relevant software. You could then also have a scale model of the archaeology with the 3-D printer if you want to have a scaled-down model, which would be great for explaining sites to the public.

4. Far from being the University-only subject that it is today, geophysics (in my opinion) could and should be taught in schools that have a science element. My reasoning? All geophysics generally requires from an individual is:

  • To be able to walk normally for an extended period of time
  • To be able to understand some physical principles about waves, electricity and magnetism (although LIDAR is not quite so simple)
  • To be diligent with equipment (its all a bit expensive).

Some schools do A-levels in archaeology where the use of archaeological geophysics is discussed. If you did phyiscs at A-level or even at GCSE then magnetism, radar frequencies and electrical resistance should be all you need to understand for the job (to being with). One could argue that because it could be taught in a school and not a university environment however, it shouldn't need the University degree (from the jobs I've applied to, many ask for at least a postgraduate degree in a trainee position!!). But I feel that archaeological geophysics is a wonderful subject and should be used by kids to inspire them to get involved with archaeology and/or science.

However, on the other side of the coin University departments are really the only ones that can afford the equipment and justify its expenditure because they will adhere to research frameworks or commercial use where geophysics is justified. Furthermore it is easier as a University student to understand the benefits of geophysical survey as part of a holistic (that is a complete) archaeological investigation, which include map regression, historical analysis, field surveys, photogrammetry, excavation/watching briefs and post excavation, etc. However schools shouldn't have to justify themselves in this way and simply say that its for the long term benefit of the children and the world as a whole, especially since geophysics has directly transferable skills to many other subjects.

5. It really works the muscles! The equipment used in geophysics is varied but they all share one thing in common- the need to move equipment around. Often it's quite manageable but it doesn't mean that it's easy work to begin with. Even as an healthy individual my body took a few days to get used to the aches from a full day of geophysics.
Back when I wasn't getting paid to walk in fields with expenive equipment...(lifted from one of my earliest blog posts , see here!)

This blog post is a tribute to Joe Raine, as recommended by a certain individual (you know who you are).