Demonstrates the application of modelling gamma-ray spectrometry and DEM for mapping regolith materials and in predicting salt stores.

In several Australian regions severe wind is projected to increase in severity as a result of climate change. This poses problems for existing buildings which are already structurally substandard under present climate and represent a high community risk. Increased severe wind gust likelihood will greatly exacerbate this as damage increases very sharply with increasing wind speed. Increasing wind hazard also presents challenges for regulators who set the design standards for future building construction. Key to adapting both legacy structures and to constructing future infrastructure compatible with future hazard is a reliable means for quantifying the benefits of adaption strategies. In this presentation work led by Geoscience Australia in collaboration with James Cook University and JDH Consulting is described. With funding contributions from the Federal Department of Climate Change a simulation tool is being developed and refined that quantitatively assesses damage to specific building systems as a result of severe wind exposure. The simulation tool accounts for variability in wind profile, shielding, structural strength, pressure coefficients, building orientation, building component weights, debris damage and water ingress via a Monte Carlo simulation approach. The software takes a component-based approach to modelling building vulnerability based on the premise that overall building damage is strongly related to the failure of key connections and members. If these failures can be ascertained, and associated damage from debris and water penetration reliably estimated, scenarios of complete building damage can be assessed and quantified in repair terms. Further, the building elements primarily responsible for failure can be identified and a range of adaptation measures simulated to quantitatively assess the benefits of structural and architectural changes now and into the future.

No abstract available

Mapping technologies have allowed scientists to effectively and rapidly characterize the seabed in shallow and deep-water systems over large areas. This, in turn, allows management to make informed decisions regarding effective marine habitat conservation. To characterize the abiotic and biotic benthos within five estuaries in South-Western Australia, we conducted a towed-video survey following the protocol of Anderson et al., 2007 that rapidly characterizes the seabed in real time at 30 second intervals. A combination of towed-video transects, run perpendicular to the shoreline, and drop-camera stations, run throughout the basin of each estuary, were undertaken. The GPS locations and benthic characterizations taken along each transect and at each drop-camera station were recorded in real time using GNav (© Gerry Hatcher, 2002). Seabed characterizations recorded include; bottom type, bedform relief, submerged aquatic vegetation cover and length and the occurrence of macro-flora and fauna. Following the field survey, data were mapped in ArcGIS to identify benthic spatial distribution patterns of seabed features. A summary of the methodology used and results will be presented. The resulting video data are also being tested for repeatability between observers. The results found from this survey will help to reveal benthic substratum patterns in estuarine habitats and differences in habitat configurations between the estuaries. The methods used to map these estuaries can be used to map other estuaries in the future.

Identifying potential leakage zones and recharge pathways is critical to constraining models of surface-groundwater interaction in many floodplain environments in semi-arid landscapes. In this study, a 300 KHz Multibeam sonar was used to map river bed morphology along a losing reach of the Darling River near Menidee in an area known to contain deeper `holes' in the river bed. The survey has shown that the river bed had a strong bar and riffle morphology, with deeper scoured reaches alternating with shallow reaches marked by oblique linear to parabolic sand bars. Sharp bends were often marked with large depressions ranging from 5 to 11 m deep. These features, locally termed `cod holes' due to their importance in providing a reliable water source and refuge for aquatic species in times of drought, are 10-40 m wide and 50 -120 m long. Tree debris is absent from these deep depressions, which when sampled in a number of locations are lined with a hard clay. Their location at sharp bends indicates that they most likely formed and kept open by river scour. The high resolution of these data has enabled construction of detailed hydrogeological cross-sections that, when combined with hydrograph analysis hydrogeochemical and geophysical data, has helped constrain models of surface-groundwater interaction. These data have also assisted in assessing the connectivity between the river and the deeper semi-confined aquifer, and assisted with assessing the potential impacts on the river of managed aquifer recharge options in the area.

Crustal magnetism is caused by the magnetic properties commonly due to ferrimagnetic minerals, especially magnetite and/or titano-magnetite, distributed in rocks throughout the crust. One of the common visualisation tools of these properties is a total magnetic intensity (TMI) map or image, from which a number of tectonic and structural inferences regarding the cause of this distribution can be made. However, one often overlooked, and important attribute of magnetism, is the fact that magnetisation is strongly temperature dependent, and ferrimagnetic material lost its properties at the Curie temperature. Generally, temperature in the crust increases with depth. Therefore, with the known magnetic mineral assemblages of the crust and geothermal gradient it is theoretically possible to calculate the 'Curie depth', where the minerals with the ferrimagnetic property become paramagnetic. Alternatively, where the vertical distribution of magnetic minerals in the crust is homogeneous, the 'Curie depth' can be estimated from spectral analysis of magnetic data. It is the depth of bottom of the magnetic anomaly source that is inferred to be a proxy for the 'Curie depth'. We have generated a new 'Curie depth' map over the Olympic Dam supergiant iron-oxide-copper-gold-uranium mineral system in the Gawler Craton of South Australia. The area benefits from high quality airborne TMI data, as well as magnetotelluric and deep seismic reflection data, and numerous local heat-flow determinations.

In late October 2010 the NSW State Water Commission began releasing 17 GL down the Darling River from the weirs at Menindee. This was the largest water release since 2001 and the first since then to begin to inundate the floodplain. Working in the area at the time provided a unique opportunity to observe how water encroaches on a floodplain at one specific location after nearly a decade of drought.

The theoretical surface Bidirectional Reflectance Distribution Function (BRDF) has a close relationship with surface cover and structure. However, there is recent debate about the ways in which surface BRDF shape derived from satellite observations can be interpreted in terms of changes in landcover, climate or vegetation structure over time scales ranging from intra-annual to decadal. For example, some found few distinguishable BRDF shape pattern differences between various landcover types using POLarization and Directionality of the Earth's Reflectances (POLDER) data. However, others have found relationships between the shape function, vegetation structure and fractional cover. In this study, 11 years of MODIS BRDF model parameter products were used to explore the seasonal and annual variation in the BRDF shape over Australia to develop insights into its relationship with cover structure. This study has the practical aim of developing a reasonable approach to default BRDF information that could be used for atmospheric correction of Landsat-scale data at times when no MODIS or other similar observational data are available.

Quantifying biodiversity is a challenge for answering scientific as well as conservation management questions. As biodiversity can only be assessed with biological samples collected by surveys, modelling process therefore need to incorporate how the adopted sampling scheme may affect resulting biological samples. Often no attempt is made to estimate the effect as it likely requires extra surveys to undertake, which is usually unacceptable overhead in marine science. However, this issue has been well recognised and investigated in different context with different terminology. This talk focuses upon a particular type of sampling scheme called sub-sampling being widely used in marine surveys. We quantify its effect as attenuation of species abundance distributions (SADs), which is defined as a vector of size index of species abundance, and demonstrate an approach for biodiversity modelling to take into account the effect. Sub-sampling is a sampling scheme that deducts a part from the whole species composition caught in marine surveys. This reduces amount of samples to store, given limited storage place on research vessels, particularly for large scale surveys. Its sampling process may simply be modelled as random sampling without replacement using multivariate hypergeometric distributions. This allows to describe how sub-sampling may change the shape of SADs. The probability of a species being absent in a subsample is also derived as $(1-r)^N$ where $r$ is sub-sampling ratio and $N$ is the number of individuals of a species in the whole catch. This type of attenuation can be taken into biodiversity modelling without extra survey work. A framework and modelling approach are demonstrated and discussed on a particular type of species distribution model. The influence of ignoring the sub-sampling effect is also discussed with data collected by a marine survey undertaken in the northern Australia.

No abstract available