Question

Analyse the performance efficiency of GPR radars and discuss in detail how they are effectively used in archeological applications. Support your discussion by theoretical concepts, researching, reviewing literature (3-4 articles), organizing and producing a write-up of not more than 800 words.

Answer 1

Solution:

GPR stands for Ground-penetrating Radar, basically, it comes under the geophysical method in which we use the radar pulse to image the subsurface.

Basically this method is non-destructive in nature and uses the High-frequency portion of the EM spectrum. Here reflected signals from the subsurface are detected.  

Operating Frequency range of GPR: 10MHz to 2.6GHz

As the depth of penetration of any EM wave is inversely proportional to the frequency of the EM wave i.e.

Depth of Penetration = 1/Frequency of wave

Hence EM wave with Higher frequency can penetrate up to shallow depth inside the earth.

Note: Reason because higher frequency get attenuated more when travels inside earth surface

The physical property measured in GPR is dielectric permittivity.

Application of GPR in Arechealogical Investigation:

Earlier times when geophysics was not there, archeologists use to excavate for exploration purposes. The use to dig a big area using the shovel kit method, and after finding Artifacts they use to proceed further. But this method was very intensive, labor & time intensive.

Role of GPR in present scenario:

Nowadays GPR is used as the 'First Phase' tool for investigation in archaeological sites. As GPR is sensitive to locate such sites, besides that it is non-destructive in nature, so proven as environment-friendly technique. GPR has basically 3 component system i.e. Control unit, Antenna, Power supply.

The Working Principle of GPR is by sending tiny EM pulses of energy inside the earth using a transmitter antenna. The reflected signals are detected by the receiver antenna (integrated with a computer-based control system). Thus after processing the data, special geological features are marked on the image, and interpretation is done after.

It can work very well in dry sandy soil where signals are easily get penetrated inside the earth's surface.

GPR can detect Metal pipes, underground artifacts, historical underground sculptures, etc.

Case History:

1. Two Brazilian archaeological sites named as Serrano and Morro Grande was investigate using GPR only. In this study area, GPR detected several pottery artifacts, including funerary urns, which was buried under the layers of sand & clay.

Here they have used 200 & 400 MHz antennae for transmitting the radar pulse. Basically they have found a great contrast of dielectric permittivity b/w target & host media, in order to successfully found these two areas.

2. GPR was used for finding the archaeological features in ancient capital of Egypt.