1882 (明治15) 年7月25日沖縄島南部の被害地震の発見

抄録

The records on a disastrous earthquake of July 25, 1882, southern Okinawa Island were discovered for the first time from nine archives. The most important are: “Okinawa-nisshi” written by Hatakeyama, a secretary of prefectural governor Uesugi; “Ryukyu-iki-nisshi” written by Ozaki, high official, dispatched from the central government to inspect a political situation in the Okinawa Prefecture; the official diary of the Okinawa Prefecture; and, the official document from the Okinawa Prefecture to the central government. Synthesizing these records, the earthquake happened between 1 and 2a. m., on July 25th, 1882, and aftershocks were intermittent for seventy days following. While there were no casualties, 500 stone walls were broken in Naha City. Analysing these records, the seismic intensity of this earthquake was probably 5. The reason why this earthquake was not discovered for about one hundred years is, firstly, the records of “Kyuyo”, an official document of the Ryukyu Kingdom, had already stopped, because the Kingdom was ruined three years before the earthquake, and secondly, the Japanese earthquake observation system was insufficient at the time of the earthquake.