Answer:
Ground Penetrating Radar (GPR)
Explanation:
Ground Penetrating Radar is a non-destructive testing method that uses electromagnetic radiations of the microwave band range of very high frequency and detects them after the reflection from the subsurface.
It is a geophysical method of subsurface imaging.
It is used to study the underground water, bedrocks, archaeological artifacts and features, detection of unexploded ordnance and detecting tunnels.
