Magnetotelluric data were acquired for Geoscience Australia by contract along the north-south 08GA-C1-Curnamona seismic traverse to the east of Lake Frome from November 2008 to January 2009 as part of the Australian Government's energy security initiative. 25 sites were spaced an average of 10 km apart, and five-component broadband data were recorded with a frequency bandwidth of 0.001 Hz to 250 Hz and dipole lengths of 100 m. Apparent resistivity and phase plots are presented, along with dimensional analyses of the data based on rotational invariants, the representation of the data by the phase tensor, and Parkinson arrows. These analyses provide insight into the complexity of the Earth conductivity giving rise to the MT responses and are a useful precursor to modelling.

Magnetic field interpretation is not an alternative to palaeomagnetic methods of recovering remanent magnetization information, both because it deals with the resultant of induced and remanent magnetizations and because confidence in recovered magnetization directions cannot match than provided by direct palaeomagnetic measurement. Nevertheless, magnetic field interpretation is highly complementary to palaeomagnetic studies. Palaeomagnetism provides detailed information from small, localised samples whereas magnetic field interpretation provides estimates of the bulk magnetization of substantial volumes (which may be completely buried and un-sampled by boreholes). Without palaeomagnetic and rock magnetic studies much of the geological information latent in magnetic field measurements cannot be accessed, and without the coverage of magnetic field data the extents and relationships of subsurface magnetization events revealed by palaeomagnetic studies cannot be fully mapped.

Now in its third year, Geoscience Australia's Onshore Energy Security Program has acquired several suites of regional geological and geophysical data. The data include several deep seismic reflection surveys that have been designed to image: - basement provinces with high geothermal gradients that may contain Uranium enrichments and are potential candidates for geothermal energy, - geological terrane boundaries and - sedimentary basins that are known to host petroleum system elements but are under-explored. Seismic signals are recorded down to 20 seconds two-way-time (TWT) which corresponds to 25-35 km depth depending on dominant lithologies. Basinal sections normally extend down to 6-8 secTWT and the data is of such high quality that any section of the seismic profile can be enlarged without significant loss of resolution. Deep reflection surveys are able to image the relationship between crystalline basement and overlying basin sequences very clearly and also allow interpretations of structural styles as well as impacts of deformational processes on the basin-fill. A new basinal section was discovered beneath the Eromanga Basin suite of sediments. Named the 'Mullangera Basin', its structural style and basement relationship seem to indicate some affinity with the Georgina Basin further west. The succession is clearly composed of several sequences that contain both fine-and coarse-grained sediments. If a geological relationship with the Georgina Basin can be ascertained, a new hydrocarbon prospective area could be delineated. Another new section was discovered beneath the Devonian section of the Darling Basin. Judging by the fast acoustic velocities the entire basin-fill sequence appears to be very dense and therefore largely non-porous and of low permeability.

An orogenic cycle typically follows a sequence of events or stages. These are basin formation and magmatism during extension, inversion and crustal thickening during contractional orogenesis, and finally extensional collapse of the orogen. The Archaean granite-greenstone terranes of the Eastern Yilgarn Craton (EYC) record a major deviation in this sequence of events. Within the overall contractional stage, the EYC underwent a lithospheric-scale extensional event between 2665 Ma and 2655 Ma, resulting in changes to the entire orogenic system. These changes associated with regional extension include: the crustal architecture; greenstone stratigraphy; granite magmatism; thermo-barometry (PTt paths); and structure. Synchronous with these changes was the deposition of the first significant gold, and it is likely that the intra-orogenic extensional event was one of the critical factors in the region's world-class gold endowment.

Summary of GA's plans for marine seismic and reconnaissance surveys off southwestern Australia in 2008/09 as part of the Offshore Energy Security Program

No abstract available

A study of the consistency of gust wind speed records from two types of recording instruments has been undertaken. The study examined the Bureau of Meteorology's (BoM) wind speed records in order to establish the existence of bias between coincident records obtained by the old pressure-tube Dines anemometers and the records obtained by the new cup anemometers. This study was an important step towards assessing the quality and consistency of gust wind speed records that form the basis of the Australian Standards/NZ Standards for design of buildings for wind actions (AS/NZS 1170.2:2011 and AS 4055:2006). The Building Code of Australia (BCA) requires that buildings in Australia meet the specifications described in the two standards. BoM has been recording peak gust wind speed observations in the Australian region for over 70 years. The Australia/New Zealand Wind Actions Standard as well as the wind engineering community in general rely on these peak gust wind speed observations to determine wind loads on buildings and infrastructure. In the mid-1980s BoM commenced a program to replace the aging Dines anemometers with Synchrotac and Almos cup anemometers. During the anemometer replacement procedure, many localities had both types of anemometers recording extreme events. This allowed us to compare severe wind recordings of both instruments to assess the consistency of the recordings. The results show that the Dines anemometer measures higher gust wind speeds than the 3-cup anemometer when the same wind gust is considered. The bias varies with the wind speed and ranges from 5 to 17%. This poster presents the methodology and main outcomes from the assessment of coincident measurements of gust wind speed.

Climate change is expected to increase severe wind hazard in many regions of the Australian continent with consequences for exposed infrastructure and human populations. The objective of this paper is to provide an initial nationally consistent assessment of wind risk under current climate, utilizing the Australian/New Zealand wind loading standard (AS/NZS 1170.2, 2002) as a measure of the hazard. This work is part of the National Wind Risk Assessment (NWRA), which is a collaboration between the Australian Federal Government (Department of Climate Change and Energy Efficiency) and Geoscience Australia. It is aimed at highlighting regions of the Australian continent where there is high wind risk to residential structures under current climate, and where, if hazard increases under climate change, there will be a greater need for adaptation. This assessment is being undertaken by separately considering wind hazard, infrastructure exposure and the wind vulnerability of residential buildings. The NWRA will provide a benchmark measure of wind risk nationally (current climate), underpinned by the National Exposure Information System (NEXIS; developed by Geoscience Australia) and the wind loading standard. The methodology which determines the direct impact of severe wind on Australian communities involves the parallel development of the understanding of wind hazard, residential building exposure and the wind vulnerability of residential structures. We provide the current climate wind risk, expressed as annualized loss, based on the wind loading standard.

Building a continental-scale land cover monitoring framework for Australia

The Australian Government formally releases new offshore exploration areas at the annual APPEA conference. In 2012, twenty-seven areas in nine offshore basins are being released for work program bidding. Closing dates for bid submissions are either six or twelve months after the release date, i.e. 8 November 2012 and 9 May 2013, depending on the exploration status in these areas and on data availability. As was the case in 2011, this year's Release again covers a total offshore area of about 200,000 km2. The Release Areas are located in Commonwealth waters offshore Northern Territory, Western Australia, South Australia, Victoria and Tasmania (Figure 1). Areas on the North West Shelf feature prominently again and include underexplored shallow water areas in the Arafura and Money Shoal basins and rank frontier deep water areas in the outer Browse and Roebuck basins as well as on the outer Exmouth Plateau. Following the recent uptake of exploration permits in the Bight Basin (Ceduna and Duntroon sub-basins) Australia's southern margin is well represented in the 2012 Acreage Release. Three new blocks in the Ceduna Sub-basin, four blocks in the Otway Basin, one large block in the Sorell Basin and two blocks in the eastern Gippsland Basin are on offer. Multiple industry nominations for this Acreage Release were received, confirming the healthy status of exploration activity in Australia. The Australian government continues to support these activities by providing free access to a wealth of geological and geophysical data.