What am I going to research?
In this case study, I am going to research what resistivity is and how a resistivity survey works using the physics principles. I am also going to explore what benefits this technique might bring, but also what flaws there could be. Additionally, I am going to explore a famous historical use of this method.
What is resistivity?
Resistivity is the oppose to conductivity. It's a measure of material's ability to oppose the flow of electric current. It is a property of the material, and it remains constant, not depending on the certain shape of the material, however it does depend on the mass and density of the particular material. The resistivity of a particular ...view middle of the document...
Soil which has a high water content will conduct electricity a lot more easily than soil which contains hard rocks, as these rocks will resist the current low. By using this information, we are able to establish the physical structure below the soil. Regions that have high resistance are likely to be buried walls or buildings where as places that have low resistance are likely to be buried ditches.
Examples of when a resistivity survey is used include determining the depth of groundwater, the location of buried sinkholes and ancient buried buildings.
Why is resistivity surveying useful and what are the complications?
One benefit of using resistivity surveying is they are able to find out what is underground without digging it up, this prevents your findings in the soil being damaged by digging, as you are able to map out where the object is, so you can be more careful when digging. It also means that when you are digging for your object, you know exactly where your object is, so you know exactly where to dig without destroying unneeded land. Similarly, it prevents you from digging up a field if there isn't anything to find after all of that, which would also be very time consuming.
Another benefit of this technique is that the tools to carry out a survey, for example a resistivity meter, are very easily obtained, even if they have highly specialised. This means that this method is very cheap compared to others. It is also possible to make 'homemade' resistivity meters that work just as well but not as accurate. This means you do not need to be highly qualified to do this and you are able to do this at home if you wanted to.
It is a technique that can be widely used for all different purposes, rather than it being a specific technique for one purpose. Here are some examples where people have been employed to investigate; the ground water depth, location of sinkholes and cavities, thickness of overburden, archaeological sites and electrical grounding of large electrical installation.
A delay in the survey could conclude from the researcher initially carrying out a investigation to establish the water content of the ground. It is very hard and time consuming to do this, and results may not be very accurate, which therefore could affect the results you conclude from it.
One disadvantage of this, is that the mineral ions contained in water are used to conduct the electrical current through the soil, this means that there must be moisture within the soil for this method to work efficiently and to find the resistance of the soil. This is a particular problem in hot countries and in the desert, for example in Egypt, they would not be able to find accurate results from this method. Furthermore, if the moisture content of the soil decreases the deeper into the soil you go, might mean that the current cannot conduct through the soil to reach the object, instead not picking up the object buried when the...