Search

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 gt 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. Language: en

A wide range of scales and indices are used to describe natural hazards and theirimpacts. Some scales infer damage levels from hazard characteristics while othersuse damage levels to estimate a physical characteristic. Damage scales may relyon raw dollar values, percent loss estimates, damage states, normalized values ormacrodamage categories. Whatever the basis of the scale it should tell the truth.However, scales are compromises between the need for detailed information andbeing simple enough to use. Damage scales may be nominal (categorical), ordinal, interval or ratio scales. Frequencywords such as ``few'', ``many'' can be dealt with in a range of ways to produce contiguous,widely separated, broadly overlapping or narrow overlapping values. Most scales rely onmaximum values but some focus on minimum or threshold values. The number of levelson damage scales commonly ranges from five to 13. Some long-lived damage scales haveevolved through several editions, changing to reflect the new or additional uses to whichthey have been put and as buildings and the nature of damage to those structures has changed. Few scales state precisely the purpose of the scale, deal clearly with ambiguities or provideguidelines for the use of qualitative information.

Information on fatalities from lightning strikes has been extracted from a specially compiled database on natural hazards in Australia. Records dating from 1803–1991 indicate that at least 650 persons have been killed by lightning strikes. Maps and charts show the percentages of victims with respect to age, sex, locality, activity, and other circumstances of the strike. The majority of the 650 fatalities recorded have occurred along the more populous southeastern coast. The overall death rate, from 1910–1989, is 0.08 per 100 000 population. The annual number of lightning fatalities has decreased with time, from a death rate of 0.21 in 1910–1919 to 0.01 in 1980–1989. This trend is more pronounced when population figures are taken into account. The group that has been most at risk in Australia is that of males aged 15–19, followed by males aged 20–34. The male:female ratio of victims has decreased with time but is not approaching equality, being 11.6 in 1910–1919 and 5.3 in 1980–1989. The diurnal and monthly occurrences of lightning fatalities peak at 12.00–18.00 hours and November-February respectively. About 86% of fatalities have occurred outdoors and 14% have occurred indoors. Approximately three-fifths of fatalities have been work-related, and the group of workers that has traditionally been most at risk is that of land-workers. Approximately one-fifth of fatalities have been recreation-related, although this proportion has been increasing with time. The recreational activities of water sports, golf, and cricket have had the greatest number of lightning fatalities. Comparisons are made between these data and the results of other similar studies, both in Australia and overseas.