The report presents results of strong-motion earthquake observation in japanese ports in 1987. Strong-motion earthquake observation results, original acceleerations and their digital tables, corrected accelerations, integrated velocities and displacements, loci of acceleration, velocity and displacement, response spectra and fourier spectra for corrected acceleration are presented with a brief explanation on the processing of digitization and correction.
　3403 records have been obtained in the network as of December 1987.
　341 records of them were obtained during 1987.
　The network consistes of 84 strong-motion accelerographs as of December 1987.
　This is 21th publication in the series.