Since 1962, strong ground motions and earthquake responses of structures have been observed in the major ports in Japan. In 2018, 2546 accelerograms were obtained and analyzed at the Port and Airport Research Institute.
The strong-motion earthquake observation network in Japanese ports consisted of 157 strong-motion accelerographs installed at 61 ports as of December 2018. Seventy-eight accelerographs out of 157 are installed on ground surface, 59 accelerographs are in ground by using bore-hole and the rest 20 are on structures such as quay walls. Six types of accelerographs were used in the network in 2018, namely, the ERS accelerograph, the SMAC-MDU accelerograph, the Omni accelerograph, the Basalt accelerograph, the CV-374 accelerograph, and the SAMTAC (SA-355) accelerograph, all of which were negative feedback accelerographs equipped with a digital recorder.
This report presents the results of observation and preliminary analysis of records obtained in 2018. ASCII data of the recorded accelerations for all the records in 2018 are available on the DVD in the user-friendly CSV format. Also, computer plots of recorded accelerations are available on the DVD for the records with peak accelerations exceeding 20 Gal. For the records with peak accelerations exceeding 50 Gal, computer plots of recorded accelerations, integrated velocities and displacements, Fourier spectra and response spectra are available on the DVD.

Key Words: earthquake, port, strong-motion earthquake observation, acceleration record,Fourier spectra