The 1994 Sanriku-Haruka-Oki Earthquake of JMA ( Japan Meteorological Agency ) Magnitude 7.5 occurred in far east off Sanriku region ( Pacific coast of north-east Honshu island ) in Japan at 21:19:20, December 28,1994. This earthquake triggered 27 accelerographs installed at 18 ports in the strong-motion earthquake observation network of the Port and Harbour Research Institute. 24 accelerograms out of 27 were obtained as digital acceleration data of three components observed in port areas in Japan.
　This report presents the strong-motion earthquake observation results of this earthquake and the results of preliminary analyses of the 21 digitized acceleration records obtained on and in ground by the main shock. The records of after shock at 00:29:29, December 30, 1994 and at 07:37:37, January 7, 1995 are also presented. Original acceleration without instrument correction, corrected acceleration, SMAC-B2 equivalent acceleration, integrated velocity and displacement, response spectra, Fourier spectra and loci of accelerations, velocities and displacements are presented as results of preliminary analyses. Amplification of accelerations of the main shock and after shocks are also presented because surface ground motion and base motion were observed simultaneously in Hakodate port, Kushiro port, Sendai port and Akita port. Attenuation relations of acceleration, velocity and displacement of main shock are also presented in this report.