Seismic data is recorded on magnetic tape in digital form and processing of the data is undertaken by digital computers. All the standard processes that are applied to reflection records prior to the interpretation of the results can be handled on a digital computer. In addition, computer programmes have been written to apply the more recently developed processes based on information theory. These processes use correlation techniques and time-domain or frequency-domain filtering to improve the quality of the reflection data. The particular noise problem associated with marine seismic data and the high outputs of marine seismic parties are efficiently handled by a digital computer. The application of correlation technique to common depth-point data provides a method of analyzing velocities within the sedimentary section. Deconvolution helps to resolve events both by shortening the reflection pulse in time and by reducing the effect of reverberations between reflecting horizons within the earth.