Geophysical Methods Flashcards
What are the advantage & caveat of the following method:
Radar
Advantage:
high resolution
Caveat:
short penetration <5m
What are the advantage & caveat of the following method:
Gravity
Advantage:
deep penetration
Caveat:
amalgamated signal, low frequency
What are the advantage & caveat of the following method:
Magnetics
Advantage:
deep penetration
Caveat:
low frequency, difficult interpretation
What are the advantage & caveat of the following method:
Telluric
Advantage:
moderate penetration
Caveat:
low frequency
What are the advantage & caveat of the following method:
Structural Geology
Advantage:
calibrated surface
Caveat:
but no direct subsurface data
What are the advantage & caveat of the following method:
Seismology
Advantage:
acceptable penetration
Caveat:
frequency loss with depth
What are the advantage & caveat of the following method:
XRF
Advantage:
geochemical data
Caveat:
a few mm penetration only
Methods of exploration geophysics
Sensed property: Gravity
Method: Density, mass
Typical targets
- Regional and local structure
- Ore bodies with large density contrasts (e.g. chromite, salt)
- Estimating total reserves
- Detecting cavities
Sensed property: Magnetic
Method: Magnetic susceptibility;
natural remnant magnetization
Typical targets
- Regional and local structure
- Magnetic ore bodies (e.g. magnetite)
- Ferrous metal deposits
Sensed property: Electromagnetic
Method: Electrical conductivity
- Regional and local structure
- Conducting ore bodies
- Groundwater exploration
- Contaminated groundwater
Sensed property: Electrical
Method: Electrical conductivity; electrical potential
- Local structure
- Conducting (or resistive) and electrically charged ores
- Groundwater and water table
- Contaminated groundwater
Sensed property: Radioactive
Method: Natural or induced radioactivity
- Radioactive minerals
- Clay and other lithologies
Sensed property: Seismic refraction and reflection
Method: Seismic velocity; acoustic impedance
- Regional and local structure
- Hydrocarbons
