Method and Applications Although geophysical techniques focus primarily on exploration for substances such as oil, water, coal and sulphides, or are applied to construction projects such as dam sites, highways, and more, applications have diversified.
Nowadays these techniques are equally suited to problems affecting the environment and urban civil engineering. The table below is set out in order of depth of investigation (from a few centimeters to several kilometers).
Methods Applications
Ground-Penetrating Radar
Underground networks (sewers, aqueducts, miscellaneous piping), shallow cavities
Pollution by hydrocarbons, determining the nature of waste material
Sounding structures, routing pipelines
Fractures
Microgravity
Shallow voids, limits of refuse tips, quality of foundations
Massive ore bodies
Ground-Based Magnetics
Eruptive rocks, faults
Mines
Environment: detection of buried ferro-magnetic objects
Seismic Tomography
Foundations and injections
Fracturing
Mining and oil exploration (static corrections for reflection seismic)
Electric Profiling and Electromagnetics with a mobile, short-distance transmitter
Salt pinch-outs, faulted or polluted zones (salt)
Thickness of weathered and decayed rock on the basement, lithological contacts.
Borehole Logging
Hydrogeology: lithology and stratigraphy, fracturing, porosity, evaluation of cementing
Mines: lithology (density, porosity)
Civil Engineering: fracturing
Hydrocarbons: static corrections and synthetic seismogram for seismic
Refraction Seismic
Thickness of the overburden
Locating the water table
Fracturing, faults
Studies of household or industrial waste dumps
Electrical Sounding
Geological exploration, water quality, large basin structure
High-Resolution Reflection Seismic
Location of specific structures for mineral water, drinking water, geothermal springs
Mining exploration (coal, pyrite, salt, potash)
Tunnel or gallery routing
Studies of underground storage sites
Magnetotellurics
Structural or stratigraphic surveys in mining, hydrocarbon and geothermal exploration
Gravity
Structural surveys: basins, domes, fault blocks, etc.
Detection of solid ores: barite, sulphides, coal, salts, etc.
