Since 1962, strong ground motions and earthquake responses of structures have been observed in the major ports in Japan. By the end of Septemberember 2001, 5978 accelerograms had been accumulated and analyzed at the Port and Airport Research Institute.
　The strong-motion earthquake observation network in Japanese ports consists of 97 strong-motion accelerographs installed at 60 ports as of Septemberember 2001. 65 accelerographs out of 97 are installed on ground surface, 28 accelerographs are in ground by using bore-hole and the rest 4 are on structures such as quay walls. In the network, three types of accelerographs have been used, namely the SMAC-B2 accelerograph, the ERS accelerograph and the SMAC-MDU accelerograph. The SMAC-B2 accelerograph is of a mechanical type and the ERS accelerograph is of an electrical type equipped with either an analogue or a digital recorder. The SMAC-MDU accelerograph is of an electrical type equipped with a digital recorder.
　This report presents results of observation and preliminary analysis of records obtained in 2001.ASCII data of the reproduced accelerograms for all the records in 2001 are available in the attached CD in user-friendly CSV format. Also, computer plots of reproduced accelerograms are available in the CD for the records with maximum accelerations exceeding 20 Gals. For the records with maximum acceleration exceeding 50 Gals, computer plots of reproduced accelerograms, integrated velocities and displacements, response spectra, Fourier spectra and loci of accelerations, velocities and displacements in horizontal plane are available in the CD.