Geology Reference
In-Depth Information
Table 1.1
Common geophysical techniques
Passive/
active
Physical property
utilised
Technique
Source/signal
Magnetics
Passive
Magnetic
susceptibility/
remanence
Earth's magnetic
field
Gravity
Passive
Density
Earth's
gravitational field
Continuous Wave
and Time-
Domain
Electromagnetics
(EM)
Active/
passive
Electrical
conductivity/
resistivity
Hz/kHz band
electromagnetic
waves
Resistivity
Imaging/
Sounding
Active
Electrical resistivity
DC electric current
Induced
Polarisation
Active
Electrical resistivity/
complex resistivity
and chargeability
Pulsed electric
current
Self potential (SP)
Passive
Redox and
electrokinetic
Redox, streaming
and diffusion
potentials
Seismic Refraction
and Reflection/
Sonic
Active/
passive
Density/elasticity
Explosives, weight
drops, vibrations,
earthquakes,
sonic transducers
Radiometrics
Active/
passive
Radioactivity
Natural or artificial
radioactive
sources
Ground Penetrating
Radar (GPR)
Active
Dielectric properties
(permittivity)
Pulsed or stepped
frequency
microwave EM
(50-2000 MHz)
Wireline Logging
Active/
passive
Various
Various
