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.

The Beagle Sub-basin is a Mesozoic rift basin in the Northern Carnarvon Basin. Oil discovered at Nebo-1 highlights an active petroleum system. 3D seismic interpretation identified pre, syn and post-rift megasequences. Pre-rift fluvio-deltaic and marine sediments were deposited during a thermal sag phase of the Westralian Super Basin. Low rates of extension (Rhaetian to Oxfordian) deposited fluvio-deltaic and marine sediments. During early post-rift thermal subsidence, sediments onlapped and eroded tilted fault blocks formed during the syn-rift phase. Consequently the regional seal (Early Cretaceous Muderong Shale) is absent in the centre. Subsequent successions are dominated by a prograding carbonate wedge showing evidence of erosion from tectonic and eustatic sea level change. 1D burial history modeling of Nebo-1 and Manaslu-1 show that all source rocks are currently at their maximum depths of burial. Sediments to the Late Cretaceous are in the early maturity window for both wells. The Middle Jurassic Legendre Formation reaches mid maturity in Nebo-1. Source, reservoir and seals are present throughout the Triassic to earliest Cretaceous, however, the absence of the regional seal in the central sub-basin reduces exploration targets. The lack of significant inversion increases the likelihood of maintaining trap integrity. Potential plays include compaction folds over tilted horst blocks, roll over and possible inversion anticlines, basin floor fans and intra-formational traps within fluvio-deltaic deposits. Late Cretaceous and younger sediments are unlikely to host significant hydrocarbons due to lack of migration pathways. Source rocks are of adequate maturity and deep faults act as pathways for hydrocarbon migration.

The Australian Government formally releases new offshore exploration areas at the annual APPEA conference. In 2011, twenty-nine areas in eight 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. 13 October 2011 and 12 April 2012, depending on the exploration status in these areas and on data availability. The 2011 Release is the largest since the year 2000 with all 29 areas, located in Commonwealth waters offshore Northern Territory, Western Australia, Victoria and Tasmania, covering approximately 200,000 km2. The producing hydrocarbon provinces of the Carnarvon, Otway and Gippsland basins are represented by gazettal blocks that are located close to existing infrastructure and are supported by extensive open file data-sets. Other areas that are close to known oil and gas discoveries lie in the Caswell Sub-basin (eastern Browse Basin) and on the Ashmore Platform (north-western Bonaparte Basin). A particular aspect of the 2011 Release is provided by 13 areas in underexplored regions offshore Northern Territory and Western Australia all of which range from 100 to 280 graticular blocks in size. These areas, located in the Money Shoal; outer Browse, Roebuck, north-eastern Carnarvon, Southern Carnarvon and North Perth basins, offer new opportunities for data-acquisition and regional exploration. The release of three large areas in the Southern Carnarvon and North Perth basins is supported by new data acquired and interpreted by Geoscience Australia as part of the Offshore Energy Security Program, of which selected results are being presented at this year's conference.

An extensive AEM survey recently commissioned by Geoscience Australia involved the use of two separate SkyTEM helicopter airborne electromagnetic (AEM) systems collecting data simultaneously. In order to ensure data consistency between the two systems, we follow the Danish example (conceived by the hydrogeophysics group from Aarhus University) of using a hover test site to calibrate the AEM data to a known reference. Since 2001, Denmark has employed a national test site for all electromagnetic (EM) instruments that are used there, including the SkyTEM system. The Lyngby test-site is recognised as a well-understood site with a well-described layered-earth structure of 5 layers. The accepted electrical structure model of the site acts as the reference model, and all instruments are brought to it in order to produce consistent results from all EM systems. Using a ground-based time-domain electromagnetic (TEM) system which has been calibrated at the Lyngby test site, we take EM measurements at a site selected here in Australia. With sufficient information of the instrument, we produce a layered-earth model that becomes the reference model for the two AEM systems used in the survey. We then bring the SkyTEM systems to the hover site and take soundings at multiple altitudes. From the hover test data and the ground based model, we calculate an optimal time shift and amplitude scale factor to ensure that both systems are able reproduce the accepted reference model. Conductivity sections produced with and without calibration factors show noticeably different profiles.

The Australian Solid Earth and Environment Grid (SEEGrid) is an eResearch infrastructure established to link diverse and distributed datasets in the geosciences, enable seamless interoperability between these, and undertake remote data processing. We present an integration between the GPlates plate-tectonic geographic information system and SEEGrid. Such a linkage is for the first time providing the necessary computational aids for abstracting an enormous level of complexity required for frontier solid-Earth research, in particular 4D metallogenesis. We present a continental reconstruction case study involving a proterozoic link between the greater Northern and Southern Australian cratons by combining evidence from several data sets. Faults are extracted from SEEGrid via Web Feature Services, and are used in conjunction with gravity anomaly data to test competing spatial alignment models of the reconstructed cratons. Additional information obtained from palaeomagnetic poles, granite geochemistry, geochronology, age-dated igneous provinces and other geophysics datasets can be used to further constrain the reconstruction. The metallogenic consequences of the best-fit reconstruction are profound, since they raises the possibility that the mineral systems hosting the giant Olympic dam, Broken Hill and Mt Isa could be linked in a particular geometry, resulting in a revised metallogenic map. The flexibility and extensibility of this spatio-temporal data analysis platform lends itself to a wide range of use-cases, including linking high-performance geodynamic modelling to kinematic reconstructions, creating the framework for future 3D and 4D metallogenic maps.

Since the 1989 Newcastle earthquake, the city of Newcastle, Australia, has become an extensive focus for earthquake hazard and risk assessment. The surficial geology varies between deeper alluvial deposits near the Hunter River, to shallower soils overlying weathered rock on the valley margins. Ambient vibration techniques, based on the dispersion property of surface waves in layered media, is one promising method for assessing the subsurface geophysical structure, in particular the shear-wave velocity (Vs). Using one such technique, the Spatial Auto-Correlation (SPAC) method, we characterise soil deposits at 23 sites in and around the city of Newcastle. Results show that values for soil overlying bedrock ranges from 200 m/s to 1000 m/s, with the higher velocity values observed in shallow soils which are relatively consolidated and far from river deposits. Bedrock depth varies from 6 to 56 m, but an accurate quantification is hampered by the low frequency picks (< 2 Hz) which are either unavailable or of dubious quality. Some shear-wave velocity profiles show two abrupt changes in Vs, the first ~ 4-15 m and the second ~19-56 m. Low Vs values are of particular interest as they may indicate areas of higher seismic hazard.

Government Geological Surveys study the Earth at the regional, province or national scale, and acquire vast volumes of technically complex data. These data must be high quality, fit for purpose, durable, and readily accessible and usable by industry. Increasingly, users require the geological information contained within the data as well as the data itself. High performance computers facilitate a step-change in advanced processing and modelling of large, complex data, and will help Government deliver more sophisticated products to industry and researchers. Data enhancement and manipulation are no-longer limited by the computational effort required, and there are no artificial limits to the size of the data or model, or the data resolution that can be processed. Geoscience Australia is collaborating with the National Computational Infrastructure facility (NCI) at the Australian National University to develop advanced methods for extracting the maximum geological information from large data volumes. The new methods include: Modelling of potential field data in spherical coordinates to create continental-scale reference models of density and magnetic susceptibility; Inversion of magnetotelluric tensor data to a full 3D mesh of resistivities, and; Monte Carlo inversion of AEM responses to assess the reliability and sensitivity of conductivity-depth images. These algorithms are being implemented in a new Virtual Geophysical Laboratory where government data and advanced processing methods are brought together in a single high performance computer environment.

Details initial algorithm development of a trans-dimensional Bayesian inversion methodology applied to remote sensing data - Shallow water bathymetry case study.