Since 1962, strong-motion earthquakes and earthquake responses of structures have been observed in the major ports in Japan. By the end of December 1998, 5503 accelerograms had been accumulated and analyzed at the Geotechnical Earthquake Engineering Laboratory of the Port and Harbour Research Institute.
　The strong-motion earthquake observation network in port areas in Japan consists of 95 strong-motion accelerographs installed at 60 ports as of December 1998. 66 accelerographs out of 95 are installed at ground surface, 22 accelerographs are in ground by using bore-hole and the rest 7 are on structures such as quay walls.
　This report presents results of observation and preliminary analysis of records obtained in 1998, which are listed in the tables of Strong-Motion Earthquake Observation Results with their maximum accelerations, being classified in accordance with earthquakes. For the records of ground motions with maximum accelerations exceeding 20 Gals (=cm/sec2), computer plots of reproduced acceleration are presented. For the records of ground motions with maximum acceleration exceeding 50Gals, computer plots of corrected acceleration, integrated velocity and displacement, response spectra, Fourier spectra, and loci of accelerations, velocities and displacements in horizontal plane are presented.