The importance of recording strong motion earthquakes was realized by harbour engineers and it was decided to install strong motion seismographs in major ports in Japan,for recording earthquake ground accelerations and structure responses to them. The installations were carried out by the Earthquke Resistant Structue Laboratory in the Port and Harbour Research Institute, in close co-operation with the Regional Harbour Construction Bureaus. The first seismograph was installed in Yokohama Port in 1962 and 49 seismographs had been installed in 27 ports up to the end of 1966. The seismographs in use are SMACB; or electromagnetic seismographs which consist of electro-magnetic transducers and magnetic tape recorders.
　This report gives the reader,the short history of the installation, the brief descriptions on the seismographs and the conditions of the installed seismographs such as the location, ground condition, base, house,directions ofcomponents and sensitivities. For the seismographs installed on structures to record structure responses, the standard cross sections of the structures are also included.