The Effectiveness of Existing Methodologies for Predicting Electrical Substation Damage Due to Earthquakes in New Zealand

This paper tests the applicability of two existing international methodologies - HAZUS (USA) and SYNER-G (Europe) - for predicting electrical substation damage. It compares observed damage from the September 2010 and February 2011 Canterbury earthquakes in New Zealand with damage/failure probabilities generated by the two methodologies based on observed ground accelerations. Only two substations were damaged in the September earthquake, and only one in the February earthquake. For both methodologies, failure probabilities were calculated for each substation and a short Monte Carlo simulation exercise was run in which the probabilities were used to generate 1,000 potential city-wide damage scenarios. Both simulations yielded results which over-predicted the collective level of damage, with probabilities of less than 1 in 1000 that the observed scenarios could occur. This indicates that neither method is appropriate and that new fragility functions should be developed for New Zealand for future seismic risk assessments.