Digital Archiving of Bromide Paper Records of Ground Tilt Observed in Kii Peninsula, Japan

Abstract:

Tilt data recorded at two observatories in the Kii Peninsula, southwest Japan are digitally archived. The observatories have been operated by the Disaster Prevention Research Institute, Kyoto University. At Kishu and Yura observatories, ground tilt was recorded on bromide (light-sensitive) papers until at least 1974. The bromide records are stored at the Abuyama Observatory at Kyoto University. At the Kishu observatory, horizontal-pendulum tiltmeters were installed in 1947. The original tilt records until at least 1974 were drawn on bromide papers with a length of 30 cm and height of 8.5 cm, and the recording speed was about 0.2 cm/h. The observation period, as well as note for change in recording speed and the occurrence date of the earthquakes, was recorded on the back of the paper. The records at Kishu observatory were investigated to detect possible slow slip event beneath the Kii Peninsula in 1973, which is a good example of reexamination of historical records based on modern knowledge of seismology.

An opensource software, Omeka, is used to build the archive. Omeka provides "web publishing platforms for sharing digital collections" and intensively used for digital museum and archives. The development costs and need for technical knowledge for implementation of the archive are reduced by introducing Omeka.

Digital images of bromide records and metadata for each record are registered to Omeka. The place of observatory and time period of observation is linked to each image, which help to find targeted record. Since the images published in the archive are compliant to International Image Interoperability Framework (IIIF), users can display or process the records using any IIIF-compliant viewer.