Authors / CoAuthors
Schofield, A. | Arthur, C. | Cechet, B.
Abstract
Tropical Cyclone Tracy impacted Darwin early on Christmas Day, 1974. The magnitude of damage was such that Tracy remains deeply ingrained in the Australian psyche. Since 1974, the population of Darwin has grown rapidly. As such it is desirable to know what impact an event similar to Tracy would have on the present day built environment. To assess the impacts in 1974 and the present day, we apply the Tropical Cyclone Risk Model (TCRM) developed at Geoscience Australia. The TCRM is used to produce a wind field consistent with the sparse meteorological observations made in Darwin during the passage of TC Tracy. A parametric wind field is calculated using the Holland radial wind profile coupled with the Kepert boundary layer model, and is further modified by incorporating localised windfield multiplier effects. The resulting wind field predicts maximum wind gusts at Darwin Airport of 72 m.s-1, which matches the estimated maximum wind speed at that location. The wind field generated with TCRM is applied to building damage models in an attempt to reproduce the widespread damage to residential structures associated with TC Tracy in 1974. Employing these models yields a mean damage estimate of 36%; a figure lower than that determined by the post-event damage survey. The unaccounted impact of large windborne debris is one possible explanation for the discrepancy between the observed and simulated damage. Based on the satisfactory replication of the damage associated with the historical impacts of TC Tracy, the wind field is then applied to the current day residential building database. We find that the mean damage to Darwin for the same urban footprint as the 1974 analysis in the present day would be around 5%. This represents an approximately 90% reduction in the modelled damage, and a significant portion of this reduction can be attributed to building code improvements.
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nonGeographicDataset
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70390
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- External Publication
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2010-05-05T00:00:00
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