A system of delta modulation with magnetic-tape recording is proposed. It should achieve excellent signal-to-noise ratio without excessive equipment complexity. The system would be of use in crustal seismology where large signal-to-noise ratio is more important than minimum channel bandwidth. The recording of data in binary form as achieved by delta modulation eliminates tape transport wow and flutter and certain other noise components found in analog recording. Compared to FM recording, delta modulation provides similar complexity of recording and nearly identical "quick-look" playback equipment. Delta modulation has the advantage, in common with other digital systems, that, with more complete playback equipment (either analog or computer), excellent removal of transport speed variations is possible. Delta modulation is less complex than other digital-recording systems, and combines many of the best features of both the digital and analog techniques.