Acquisition of seismic exploration data involves the synthetic generation of seismic waves, and their subsequent detection after passing through or reflecting off the region of interest (i.e., the "target"). The most frequently practiced form of seismic acquisition is the reflection seismic survey.A reflection seismic survey typically involves generating hundreds to tens of thousands of seismic source events, or shots, at different locations in the survey area. The seismic energy generated by each shot is detected and recorded at a variety of distances from the source location. The detectors used to transform ground movement into an electrical voltage that can be recorded are geophones, generically referred to as receivers. When an earthquake or explosion happens, shock waves, also called seismic waves, travel through the ground and reflect off rocks in the subsurface the same way that ripples in a pond reflect off a boat in the water.Because boundaries between different rocks often reflect seismic waves, geophysiscists use these waves to generate pictures of what the subsurface looks like. It is much the same as using sonar to create a profile of the ocean floor, except seismic waves are used instead of sound waves. Dynamite explosions or vibrator trucks are used to create the seismic waves, and geophones laid out in lines measure how long it takes the waves to leave the seismic source, reflect off a rock boundary, and return to the geophone. The resulting two-dimensional image, which is called a seismic line, is essentially a cross-sectional view of the earth oriented parallel to the line of geophones.