INFLUENCE OF EARTHQUAKE MONITORING SYSTEM ON EMERGENCY SHUTOFF DECISION OF CITY GAS SUPPLY

Abstract

 We proposed an evaluation method for the influence of earthquake monitoring system on emergency shutoff of city gas supply. Firstly, assuming random selection of locations of seismometers or incidental missing of observation, the effects of change in “k-out-of-n shutoff system” on shutoff probability were probabilistically modeled using hyper geometric distribution. Secondly, assuming planned selection of locations, increase, decrease or relocation of seismometers, relative importance of individual seismometer within a service block was evaluated on the basis of weighting factors calculated through the application of Ordinary Kriging for spatial interpolation of shaking intensity. Estimation variance with respect to spatial interpolation was also evaluated for a group of seismometers within a service block. We discussed the optimal allocation of seismometers under the restriction of the number of seismometers.