Damage costs for commercial and industrial property as a function of intensity in the 1987 Edgecumbe earthquake

This paper describes an analysis of damage costs to commercial and industrial property, including buildings (all low-rise), their contents, equipment and stock, in the M_s = 6.6 Edgecumbe New Zealand earthquake of 2 March 1987. The damage costs were converted to damage ratios by dividing by the value of the relevant property item. For the MM7 and MM9 intensity zones, the mean values and statistical distributions of these damage ratios were then found, the lognormal distribution fitting well. For all commercial and industrial buildings in the MM intensity IX zone (centroid MM9-4) the mean damage ratio was 0.076. The mean damage ratios were generally much smaller than estimated in previous studies. The buildings were all low-rise. There was no correlation between building and equipment damage ratios on a building by building basis. Considering dates of construction, it appears that mean damage levels at MM9 have not changed significantly for postcode buildings through changes in design standards up to the 1980s.