Seismic prospecting Methods

Mankind has had instruments that can measure the amplitude and the direction of shock waves produced by earthquakes. These shock waves are acoustic waves, just like sound waves. And like sound waves, they travel faster in rigid and dense bodies than they do in less rigid and less dense ones. They also reflect from the boundaries between different rock types, allowing the geologist to measure the time they take to travel and determine the structure of the rocks below.

Seismic prospecting is the most widespread geophysical method in petroleum exploration. Small artificial shock waves are generated at a selected point by either firing a charge of explosives in a shallow drill hole or dropping a heavy weight. The speed of the shock waves is measured by timing their arrival at sensitive receivers called geophones placed along the survey line.

No Best Method: There is no one best geochemical or geophysical method. Depending on the kind of deposit a prospector is looking for, one or more methods may be very useful, some may provide helpful additional information, and others may have no use at all. Usually, a well-designed exploration program uses several different methods, chosen to fit the geological environment the prospector is exploring. Often the best methods can be found by trial-and-error surveys over known mineralization in the area, a technique called orientation surveying.

Lightweight, geophysical prospecting tools are making the prospector’s task less arduous and more precise. But there is still no substitute for geological insight, and no easy road to a mineral discovery.