Investigation and Forecast Earthquake Damage for Sewerage Systems

Japan is known as one of the areas where earthquake occurs most to be located in border of oceanic plate and continental plate. On this account, earthquake countermeasures are pushed forward triggered by the great Hanshin earthquake (1995), but measures for existing facilities are not yet enough.In such situation, the mid Niigata prefecture earthquake of October 23, 2004 attacked sewerage facilities and sever damage such as conduit failure and floating of manholes took plaice. Investigation of the cause why such damage occurred, and necessity of earthquake countermeasure was reaffirmed.On these backgrounds, the factors of sewerage facilities' failure that was brought by earthquakes of the past were analyzed, and damage estimation method was developed. With this approach, effective countermeasures could be figured out by appraising damage to sewerage facilities due to predicted earthquakes.