Tropical Cyclone (TC) Tracy impacted Darwin early on Christmas Day, 1974. The magnitude of damage was such that Tracy remains deeply ingrained in the Australian psyche. Several factors contributed to the widespread damage, including the intensity of the cyclone and construction materials employed in Darwin at the time. Since 1974, the population of Darwin has grown rapidly, from 46,000 in 1974 to nearly 115,000 in 2006. If TC Tracy were to strike Darwin in 2008, the impacts could be catastrophic. We perform a validation of Geoscience Australia's Tropical Cyclone Risk Model (TCRM) to assess the impacts TC Tracy would have on the 1974 landscape of Darwin, and compare the impacts to those determined from a post-impact survey. We then apply TCRM to the present-day landscape of Darwin to determine the damage incurred if a cyclone identical to TC Tracy impacted the city in 2008. In validating TCRM against the 1974 impact, we find an underestimate of the damage at 36% of replacement cost (RC), compared the survey estimate of 50-60% RC. Some of this deficit can be accounted for through the effects of large debris. Qualitatively, TCRM can spatially replicate the damage inflicted on Darwin by the small cyclone. The northern suburbs suffer the greatest damage, in line with the historical observations. For the 2008 scenario, TCRM indicates a nearly 90% reduction in the overall loss (% RC) over the Darwin region. Once again, the spatial nature of the damage is captured well, with the greatest damage incurred close to the eye of the cyclone. Areas that have been developed since 1974 such as Palmerston suffer very little damage due to the small extent of the severe winds. The northern suburbs, rebuilt in the years following TC Tracy, are much more resilient, largely due to the influence of very high building standards put in place between 1975 and 1980.

This workshop presented the results of the Mount Isa deep crustal seismic survey to mineral explorers and other interested geoscientists. The survey was carried out in 2006 across the Mount Isa Inlier and the Lawn Hill Platform in northwest Queensland as a collaborative project between Geoscience Australia, the Queensland Government (Geological Survey of Queensland), Zinifex Pty Ltd and the Predictive Mineral Discovery Cooperative Research Centre (pmd*CRC) using the facilities of ANSIR (the National Research Facility for Earth Sounding).

DIGITAL NUMBER TO RADIANCE CALIBRATION CONSTANTS FOR ACRES LANDSAT MULTISPECTRAL SCANNER DATA

This is an extract from the ACRES Landsat Digital Data Format Document.

Since the 2004 Sumatra-Andaman Earthquake, understanding the potential for tsunami impact on coastlines has become a high priority for Australia and other countries in the Asia-Pacific region. Tsunami warning systems have a need to rapidly assess the potential impact of specific events, and hazard assessments require an understanding of all potential events that might be of concern. Both of these needs can be addressed through numerical modelling, but there are often significant uncertainties associated with the three physical properties that culminate in tsunami impact: excitation, propagation and runup. This talk will focus on the first of these, and attempt to establish that seismic models of the tsunami source are adequate for rapidly and accurately establishing initial conditions for forecasting tsunami impacts at regional and teletsunami distances. Specifically, we derive fault slip models via inversion of teleseismic waveform data, and use these slip models to compute seafloor deformation that is used as the initial condition for tsunami propagation. The resulting tsunami waveforms are compared with observed waveforms recorded by ocean bottom pressure recorders (BPRs). We show that, at least for the large megathrust earthquakes that are the most frequent source of damaging tsunami, the open-ocean tsunami recorded by the BPRs are well predicted by the seismic source models. For smaller earthquakes, or those which occur on steeply dipping faults, however, the excitation and propagation of the resulting tsunami can be significantly influenced by 3D hydrodynamics and by dispersion, respectively. This makes it mode difficult to predict the tsunami waveforms.

Fluid pathways and drivers

Map produced for the Australian Government Solicitor in December 2008 showing the Torres Strait Regional Claim (Q6040 of 2001) as mofidied and the Western Skipjack Fishery. For confidental/internal use by AGS and not for general release.

Map produced for the Australian Federal Police showing the logged positions of Vessel Immacolata on the 2nd and 3rd October 2007 on a background on AUS808 and AUS809 and the Cable Protection Zone.

Map produced for the Australian Government Solicitor in December 2008 showing the Torres Strait Regional Claim (Q6040 of 2001) as mofidied and the Northern Prawn Fishery. For confidental/internal use by AGS and not for general release.

Tunkillia Deposit Scale Modelling Factsheet