Scientists use seismic imaging techniques to map the geological structure below the earth's surface.
These maps reveal the depth and area of basins , fault networks , and the physical properties of rocks . Seismic imaging techniques have analogs in medical science. Traveltime observations and variations in amplitude, frequency, and waveform are combined to produce a model of the geologic structure. The model must be consistent with other geophysical and geological data, such as measurements of the strength of gravity, measurements of the strength of the magnetic and electric fields, and laboratory measurements of the speed of seismic waves in rock samples.