Exploration geophysics
These methods can map out sulphide bodies within the earth in three dimensions, and provide information to geologists to direct further exploratory drilling on known mineralization.
Well logging is another widely used technique as it provides necessary high resolution information about rock and fluid properties in a vertical section, although they are limited in areal extent.
This limitation in areal extent is the reason why seismic reflection techniques are so popular; they provide a method for interpolating and extrapolating well log information over a much larger area.
These can be used to determine the geometry and depth of covered geological structures including uplifts, subsiding basins, faults, folds, igneous intrusions, and salt diapirs due to their unique density and magnetic susceptibility signatures compared to the surrounding rocks; the latter is particularly useful for metallic ores.
Remote sensing techniques, specifically hyperspectral imaging, have been used to detect hydrocarbon microseepages using the spectral signature of geochemically altered soils and vegetation.
[4] Ground penetrating radar is a non-invasive technique, and is used within civil construction and engineering for a variety of uses, including detection of utilities (buried water, gas, sewerage, electrical and telecommunication cables), mapping of soft soils, overburden for geotechnical characterization, and other similar uses.
[5] The Spectral-Analysis-of-Surface-Waves (SASW) method is another non-invasive technique, which is widely used in practice to detect the shear wave velocity profile of the soil.
The SASW method relies on the dispersive nature of Raleigh waves in layered media, i.e., the wave-velocity depends on the load's frequency.
The method is fairly general, and is capable of imaging the arbitrarily heterogeneous compressional and shear wave velocity profiles of the soil.
These waves propagate through the soil, and due to the heterogeneous geological structure of the site under investigation, multiple reflections and refractions occur.
[10] Magnetotellurics has proven useful for delineating groundwater reservoirs, mapping faults around areas where hazardous substances are stored (e.g. nuclear power stations and nuclear waste storage facilities), and earthquake precursor monitoring in areas with major structures such as hydro-electric dams subject to high levels of seismic activity.
[12] The sonar transducer is able to determine both the range and orientation of an underwater object by measuring the amount of time between the release of the sound pulse and its returned reception.
[15] Since our global method of conflict resolution banks on warfare, we must be able to rely on specific practices to detect this unexploded ordnance, such as magnetic and electromagnetic surveys.
[16] By looking at differences in magnetic susceptibility and/or electrical conductivity in relation to the unexploded ordnance and the surrounding geology (soil, rock, etc.
