1 minute read

Subsurface Detection

Usefulness Of Subsurface Detection

The techniques described here are very often used together to improve our understanding of what exists below the surface. By adjusting the sensitivity of the instruments and the spacing of the measurements, the scale and the depth of interest may be varied. The same theory and principles used with magnetic techniques which delineate the rift running through the crust of North America, at a depth of 18 mi (30 km), can be used to locate buried pipes and cables at a depth of less than 10 ft (3 m).

Often, subsurface detection is the only way to study the area of interest, because it lies too deep to be reached directly. Other times it is used because it is less expensive than digging or drilling, or because it disrupts the environment less.

See also Seismograph.

Resources

Books

Press, F., and R. Siever. Understanding Earth. 3rd ed. New York: W.H Freeman and Company, 2001.

Telford, William Murray, L.P. Geldart, and R.E. Sheriff. Applied Geophysics. Cambridge; New York: Cambridge University Press, 1990.

Otto H. Muller

KEY TERMS

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reflection

—When some of the energy of a seismic wave bounces off a boundary between two media, instead of traveling through it.

Refraction

—The bending of light that occurs when traveling from one medium to another, such as air to glass or air to water.

Seismic wave

—A disturbance produced by compression or distortion on or within the earth, which propagates through Earth materials; a seismic wave may be produced by natural (e.g. earthquakes) or artificial (e.g. explosions) means.

Additional topics

Science EncyclopediaScience & Philosophy: Stomium to SwiftsSubsurface Detection - Seismic Reflection, Electric Techniques, Nuclear Survey Methods, Satellite Altimeter Data, The Inverse Problem - Potential field methods