The Great Hanshin Earthquake brings many lessons

The Great Hanshin Earthquake occurred at 05.46 a.m. on Tuesday, January 17, 1995 and it left severe damage worse than any other recorded to property, such as highways, rail lines, and buildings. This never before experienced earthquake was recorded using the Japan Meteorological Agency Scale (hereinafter seismic intensity) of VII. It had a magnitude of 7.2 and it hit Kobe directly. It also caused heavy damage to telecommunications systems including telecommunications power systems. To express seismic activity, the intensity scales used in Japan are based on the effects measured by human senses. The seismic intensity is divided into eight steps from zero to seven. NTT has implemented countermeasures to resist earthquakes taking the lessons learned from the Tokachi-offshore earthquake (1968), the Izuhantou-offshore earthquake (1974) and the Miyagi-offshore earthquake (1978), etc. into account. It was proved that the countermeasures were effective as a whole; however, NTT could not avoid damage to engine-generators and batteries. This paper describes what they learned focusing on the extent of damage restoration, and the effectiveness of the measures taken and future plans.