Oil tank with plates that deformed(buckled) in response to the strong ground motions during the 1995 great Hanshin-Awaji earthquakeWhen a large earthquake occurs, what sort of shaking will be experienced at oil tank sites? Predicting such shaking is indispensable for establishing safeguards against tank damage. Furthermore, knowing the intensity of shaking at an oil tank as soon as possible and estimating the damage caused to them, will help prevent and mitigate disasters.

To this end, we are installing seismographs at actual oil tank sites in an effort to develop a system that can collect information on shaking in quasi-real time. We are also involved in research on predicting strong ground motions at oil tank sites when large earthquakes occur. The prediction of strong ground motions is being carried out using the data from seismographs installed at oil tank sites in various regions. Thus far, we have predicted the strong ground motions at an oil tank site in the Sendai region during a hypothetical earthquake off the coast of Miyagi Prefecture. It is said that a real earthquake is very likely to occur here in the near future. In the 1978 Miyagi-ken-oki earthquake, the bottoms of oil tanks at a refinery in Sendai were damaged by strong ground motions, causing massive leaks of heavy oil.

We are developing a disaster information system that can predict tank damage before an earthquake strikes and estimate it quickly afterwards, through calculating the stress in tank shell plates and the sloshing wave height using the information on the shaking.

Example of calculation results on axial compressional stress occurring in the shell plates of an oil tank,based on predicted strong ground motions