Seismic data are usually interpreted by geophysicists or geologists. The ideal interpreter combines training in both fields. He fully understands the processes involved in the generation and transmission of seismic waves, the effects of the recording equipment and data processing, and the physical significance of the seismic data. His geologic experience helps him assimilate the mass of data, some of it conflicting, and arrive at the most plausible geologic picture. Unfortunately, not all interpreters have the requisite knowledge and experience in both geology and geophysics, and often the next best alternative is to have a geophysicist-geologist team working in close cooperation.