Probabilistic Modeling of Post-Earthquake Fire in Wellington,New Zealand

Wellington, the capital of New Zealand, has both high seismic and high post-earthquake fire risk because it straddles the highly active Wellington Fault, has many closely spaced wooden buildings, and has a fragile water supply system. Repeated modeling of a Wellington Fault earthquake showed that the distribution of fire losses was much broader than that of the shaking losses, so that while fire losses were usually much smaller than the preceding shaking losses, they could occasionally be much greater than the shaking losses. Probabilistic modeling using a synthetic catalog of earthquakes gave estimates of post-earthquake fire losses in Wellington that were relatively minor for return periods up to 1,000 years, equal to the shaking losses at about a 1,400-year level, and that dominated the losses for 2,000-year and longer return periods.