A new Damage Index

A new damage index to estimate damage to buildings relies on construction costs per square metre, and a replacement ratio which approximates costs relative to the cost of replacing a median-sized family home. Building damage is estimated against a five-point scale with Central Damage Values at 0.02, 0.1, 0.4, 0.75 and 1.0 of the replacement cost. Damage is expressed as damage in House Equivalents (HE) = Replacement Ratio x Central Damage Value. The Damage Index = log(2) ( HE) provides a simple 0 - 20 scale covering total damage of less than 1 HE to > 1 million HE. For all natural hazard impacts in Australia DI is less than 12. Where the only damage data available are of lesser quality Generic or Qualitative Damage Indices (GDI and QDI) can be used. The various advantages and limitations of the Damage Index are discussed.