INFERENCES FOR DESIGN, INSURANCE AND PLANNING FROM DAMAGE EVALUATION IN PAST NEW ZEALAND EARTHQUAKES

Abstract This paper describes the research methods, results and implications to date of an ongoing series of studies on damage, damage costs and damage ratios for various types of New Zealand property, i.e. houses and their contents, low-rise non-domestic buildings of various ages, and plant equipment and stock in various non-domestic situations. The statistical properties of the distributions of damage ratio have been evaluated as a function of Modified Mercalli (MM) intensity, up to MM10. Using the damage ratios, the relative vulnerability of different classes of buildings, equipment and stock have been evaluated. All subsets of the data (from two earthquakes of Mw6.6 and Mw7.8 respectively) were found to have damage ratios fitting the truncated lognormal distribution well. The mean damage ratios were, in general, much less than previously believed. In a microzoning study of Napier, which was close to the fault rupture of the Mw7.8 1931 Hawke's Bay earthquake, it was found that single-storey houses were...