GEOPHYSICS (GPR) Flashcards
A technique of imaging the subsurface at high resolution using a non destructive mehod and can consequently be applied in urban as sensitive environmet
Ground Penetrating Radar
What is measured in GPR?
Time for wave to be reflected and received
Energy Reflected is a function of
Moisture Content
Density
(SOIL PROPERTIES)
Where iS GPR Analogous
Xray of the pavement section with color coding scheme
Trend of GPR Data?
Greater the anomaly - Larger the amplitude
Data used to create the image of the underground?
Time and Amplitude Wavelength
Ability of material to store and allow passage of electromagnetic energy when a field is imposed upon it (Ability to accept EM energy)
Relative Dielectric Permitivty
Formular for GPR Depth determination
D= (5.9*T)/Square root of Dielectric Constant
unit is in inches
What sets GPR from seismic
Similar images
Limited penetration few tens of meters
MAY STOP AT WATER TABLE usually very strong reflector
Transmitters and antenna are kept at a small fixed separation
Reflection Profiling
Transmitter and anternna are moved apart about a fixed central point
Velocity Sounding
Transmitter and anternna are mounted on either side of the object of interest
Transillumination
Mining and Econ Geol
?Image sed layers with Heavy minerals
?Can be used to map water table in aid of Bulk Mineral Exploration
?Can be used to locate River Paleochannels and define possible Placer Deposits
Structural
?Imaging shallow soil and Rock Structures
Hydrogeol
?Locating burried channels
?Mapping the Water Table
Environmental and Engg
?Forensic Invesitigation
Archaeology
Buried objects
