Geophysics Flashcards
Studies the structure of the Earth.
Global geophysics
It is used for detecting ore bodies, structure of trap oils; depth and configuration of aquifer.
Exploration geophysics
It is used for site investigation, contaminant studies, and archeological investigations.
Geotechnical & environmental geophysics
Enumerate the geophysical methods
Gravity
Magnetics
Seismic reflection, seismic refraction
Electrical (georesistivity, induced polarization)
Ground penetrating radar
Degree to which a substance may be magnetized
Magnetic susceptibility
Amount of deformation of a material upon removal of the stresses; elastic moduli (Young’s modulus, bulk modulus, shear modulus or modulus of rigidity)
Elasticity
Ability of a material to conduct electrical current (resistivity is the inverse of conductivity)
Conductivity
Ability of a material to transmit radar energy to depth
Relative dielectric permittivity
Parameters: Changes in strength of earth’s gravitational field
Property: Density
Depth: All
Gravity
Parameters: Changes in the strength of the geomagnetic field
Property: Magnetic susceptibility
Depth: Surface to Curie Isotherm
Magnetic
It is the bottom of magnetic layer in upper lithosphere. With increasing of buried depth, the temperature increase gradually, the minerals lose their magnetic property when the temperatures rise to ________.
Curie point/ Curie point isotherm
Parameters: Travel times of reflected or refracted seismic waves
Property: density and elastic moduli
Depth: <50 m to ~2 km (for muti-channel surveys)
Seismic
Parameters: Resistance, potential differences
Property: conductivity or resistivity
Depth: ~2 km
Electrical
Parameters: Reflection of electromagnetic waves
Property: Relative dielectric permittivity
Depth: <50 km
Ground penetrating radar
Noise is the undesirable part of seismic data that is not signal, and signal is what fits our conceptual model.
Seismic noise.
