The response of a seismometer array or “pattern” is a function of the wave length (also of the moveout or phase velocity) of incident energy. Patterns are thus “moveout filters.” The present paper develops the general theory of arrays and gives an explicit solution for the design of an array having a predetermined moveout response.
It is further shown that the antenna theory approach to pattern design is inadequate in the seismic case by reason of the non-uniqueness of the velocity of incident energy.
An example of a pattern designed to meet specific requirements is exhibited. The case presented effects a calculated improvement of at least four to one in signal-to-noise ratio over conventional patterns. The output of the designed system for a horizontally traveling, transient pulse input is shown to be greatly reduced in peak amplitude.
Results of experimental and production use of the moveout filter are presented and discussed.