Seismic investigations are commonly used to obtain subsurface data from geologic structures, stratigraphy, and water-bearing rocks. The equipment used includes a seismograph (which records and processes data), geophones (which measure ground acceleration), and an energy source (such as a plate and hammer, seismic gun, or weight-drop).

The data obtained are velocity measurements of the acoustic energy traveling through the subsurface. As the seismic waves strike a boundary between rock units with different acoustical properties, portions of the energy will be critically-refracted along the boundary or reflected back to the surface. By measuring the time, distance, and amplitude of the returned energy, interpretations can be made of the strata's geometry.

Refraction surveys measure the time and distance of the refracted seismic waves to first reach each geophone. Reflection investigations measure the time, distance, and amplitude of all the reflected seismic energy to reach each geophone.

The four major elements of a seismic investigation are: 1) the length of the survey line; 2) the survey line location; 3) the geophone spacing; and, 4) the energy source. The length and location of the survey line is dictated by the areal extent of the study area. The geophone spacing is dependant on the desired depth of investigation and the seismic velocities of the rock units encountered. A plate and hammer is often used if the desired depth of investigation is less than 20 meters. For deeper investigations, a seismic gun or weight-drop is employed.

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