ABSTRACT: A summary of formulas for calculation of tidal accelerations due to the moon and the sun were compiled for computer use by I.M. Longman in 1959. On the basis of Longman's formulas we developed a Fortran IV program (PRETID) to predict tides for specified time intervals at any point on the surface of a rigid earth. Output from the program PRETID consists of a printout of tidal values in milligals with a corresponding line printer plot. Test cases comparing results with standard EAEG (European Association of Exploration Geophysicists) tables show reliability of the program.

Rudman, A. J., Ziegler, R., and Blakely, R. F., 1977, Fortran program for generation of earth tide gravity values: Indiana Geological Survey Occasional Paper 22, 14 p., 1 fig., 4 app.

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Keywords: gravity, program, geophysics

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