Geoscience Australia is custodian of ship-track magnetic and gravity data from close to 700 marine surveys conducted between 1960 and 2009. These data were last combined and levelled in the late 1990s. New levelling has been motivated by specific requirements within projects being conducted as part of the Australian Government's Energy Security Program (2006-2011). These projects rely on marine potential-field datasets to help constrain sediment thickness and basement architecture in remote offshore basins. Recently-levelled datasets cover: 1) the Capel and Faust basins, deepwater basins about 800 km off the east coast, and 2) the southwest margin of the Australian continent. The levelling involved the following steps: consistent computation of gravity anomalies; splitting lines into straight-line segments to facilitate cross-over computations; low-pass line filtering where necessary; editing to remove problematic ship-tracks; and levelling to minimise cross-over misties. Using methods developed by Intrepid Geophysics for the late-1990s Australia-wide work, magnetic data were levelled by minimising misclosures around loops and then gridded and merged with aeromagnetic data in onshore and near-shore areas. Gravity data were levelled using a polynomial technique and satellite-altimeter-derived gravity data as a reference surface. The resulting levelled datasets provide information at a higher-resolution than is available from satellite-derived gravity measurements or from global compilations of magnetic data. Despite this, the levelled datasets are limited to areas of specific scientific or exploration interest, which highlights the need for levelled datasets that cover the whole of Australia's marine jurisdiction.

The Sustainable Management of Coastal Groundwater Resources (SMCGR) project aims to improve the management of groundwater in coastal dune aquifers, which is used to supply water for coastal communities in the Mid North Coast region. There is increasing pressure on groundwater resources from expanding urbanisation and tourism in this region, which has made sustainable management of existing groundwater supplies an important issue for coastal communities and councils. Over extraction from groundwater systems can affect the water available for ecosystems, which may be dependent on shallow groundwater resources. Withdrawal of groundwater resources in excess of the sustainable yield may also result in fresh water resources being degraded by seawater intrusion or by upcoming from underlying saline water bodies.

Probabilistic seismic-hazard analyses (PSHAs) require an estimate of Mmax, the magnitude (M) of the largest earthquake that is thought possible within a specified area. In seismically active areas such as some plate boundaries, large earthquakes occur frequently enough that Mmax might have been observed directly during historic times. In less active regions like Australia, and most of the Central and Eastern United States and adjacent Canada (CEUSAC), large earthquakes are much less frequent and generally Mmax must be estimated indirectly. By virtue of a fortuitous combination of climatic conditions, geology and geomorphology, Australia boasts arguably the richest Quaternary faulting record of all the world's SCR crust. Extensive consultation amongst the geological community, and recent advances in digital elevation model coverage, have allowed the compilation of an inventory of over 200 landscape features consistent with fault scarps relating to Quaternary surface breaking earthquakes across Australia. Variations in the character of these scarps, when considered together with large-scale geological and geophysical variations, justify the division of the continent into six onshore 'neotectonic domains'. Within each domain, mean Mmax has been calculated from the 75th percentile scarp length by averaging the earthquake magnitudes predicted by several published relations. Results range between M7.0-7.5±0.2. While this approach is inherently conservative, extreme values relating to multiple event scarps, which cannot be confidently discriminated without field validation, are removed. Consequently, in several cases our data represent an underestimate of 0.1-0.2 magnitude units relative to calculations based upon rare palaeoseismic data. Nevertheless, our findings indicate the potential for M>7.0 earthquakes across Australia, and by proxy analogous crust in the CEUSAC and elsewhere, and thereby have the potential to significantly reduce uncertainty in PSHAs.

A challenge for climate change researchers and planners alike is to understand the urban form in the future to assess needs and risks. Most impacts of climate change won't be clear until 2050 or later, however population projections, dwelling projections and development plans generally go no further than a 30 year time period. This leaves a gap in the understanding of the urban form between the end of the projections and future climate change impacts. Geoscience Australia in partnership with the Department of Climate Change and Energy Efficiency is developing a method that can model the urban form and adaptation scenarios. The method is based on existing models, but is generalised to enable linkage to the National Exposure Information System (NEXIS) and be implemented in a nationally consistent manner. The model is focussed on building vulnerability, namely building age, but implementing social vulnerability is also being considered.

In mid 2010 an Indonesian team of scientists and practicians published the new Indonesian probabilistic seismic hazard analysis (PSHA) map. The new PSHA map will replace the previous version from 2002. One of the major challenges in developing the new map is that data for many active fault zones in Indonesia is sparse and mapped only at the regional scale, thus the input fault parameters for the PSHA inheret unavoidably large uncertainties. Despite the fact that most Indonesian islands are teared by active faults, only Sumatra has been mapped in sufficient detail. In other areas, such as Java and Bali, the most populated and developed regions, many active faults are not well mapped and studied. These include the well known Cimandiri-Lembang fault in west Java and the Opak fault near Jogyakarta that released the destructive M6.3 Yogyakarta earthquake in 2006. This year we start a national program to systematically study major active faults in Indonesia. The study will include the acquisition of high-resolution topography and images required for detailed fault mapping, measuring geological sliprates and locating good sites for paleoseismological studies. We will also conduct GPS-campaign surveys to measure geodetic sliprates. To study submarine active faults, we will collect and incorporate bathymetry and marine geophysical data. The research will be carried out, in part, through masters and Ph.D student thesis in the new graduate study program and research center, called GREAT - CrATER (Graduate Research for Earthquake and Active Tectonics and Center for Active Tectonics and Earthquake Research), hosted by LIPI and ITB, in partnership with the Australia-Indonesia Facility for Disaster Reduction (AIFDR). In the first four years of the program we will select several sites for active fault studies, particulary faults that pose the greatest risk to society.

This document presents an assessment of five earthquake scenarios for Adelaide, South Australia. The earthquake scenarios occur on the Para Fault that runs beneath the Adelaide urban area and are aligned with recurrence intervals of 100, 500, 1000, 10,000 years and the maximum magnitude earthquake possible on the fault (approximately 1 in 20,000 year event). The events selected are hypothetical and are underpinned by the current understanding of the earthquake hazard in the Adelaide region.

Geoscience Australia is currently drafting a new National Earthquake Hazard Map of Australia using modern methods and models. Among other applications, the map is a key component of Australia's earthquake loading code AS1170.4. In this paper we provide a brief history of national earthquake hazard maps in Australia, with a focus on the map used in AS1170.4, and provide an overview of the proposed changes for the new map. The revision takes advantage of the significant improvements in both the data sets and models used for earthquake hazard assessment in Australia since the original maps were produced. These include: - An additional 20+ years of earthquake observations - Improved methods of declustering earthquake catalogues and calculating earthquake recurrence - Ground motion prediction equations (i.e. attenuation equations) based on observed strong motions instead of intensity - Revised earthquake source zones - Improved maximum magnitude earthquake estimates based on palaeoseismology - The use of open source software for undertaking probabilistic seismic hazard assessment which promotes testability and repeatability The following papers in this session will address in more detail the changes to the earthquake catalogue, earthquake recurrence and ground motion prediction equations proposed for use in the draft map. The draft hazard maps themselves are presented in the final paper.

This is a round-Australia fly through for the Land Cover Map of Australia from 2000-2008

For the last 50 years, Geoscience Australia and its predecessors have been collecting onshore near-vertical-incidence deep seismic reflection data, first as low fold explosive data and more recently as high fold vibroseis data. These data have been used in conjunction with other seismic data sets by various research groups to construct depth to Moho models. The Moho has been interpreted either as a strong reflector per se, or as the bottom of a reflective band in the lower crust. However the amplitude standout of the Moho can be very much dependent on the fold of the data and applied processing sequence. Some low fold explosive data was re-processed by Geoscience Australia to enhance the Moho for comparison with recent vibroseis data, in the Mt Isa province in Queensland, and in the Southern Delamerian and Lachlan Fold Belts in Victoria. Marked improvement was achieved by time-variant band-limited noise suppression of reverberations, as well as by coherency weighted common mid point stacking. Post stack migration can also improve the clarity of the Moho, provided there is enough continuity of the data to avoid migration 'smiles'. An important consideration was amplitude scaling, with a time variant automatic gain control (AGC) employed before stack, and a weighted AGC applied after stack, in order to preserve seismic character. These results demonstrate that processing and acquisition issues need to be understood in order to assess the reflective character of the Moho and indeed to interpret its location.

The timing and duration of metamorphic events is commonly constrained by radiometric dating using the U-Pb or 40Ar-39Ar dating methods, or a combination of both. Each dating method can be applied to a different range of minerals, and a combination of the two methods can provide more complete timing constraints than either method on its own. Comparison of radiometric ages from different isotopic systems introduces the problem of systematic uncertainties arising from uncertainty in parameters such as decay constants and the age of method-specific reference materials. Over the past decade it has been increasingly recognized that the laboratory-based determinations of the 40K decay constants, on which the 40Ar-39Ar method is based, are relatively imprecise and that the values recommended by Steiger and Jager (1977) result in a systematic offset of 40Ar-39Ar ages relative to U-Pb-derived ages by up to ~1%. This problem has been addressed by several studies over the past decade, with the most recent study (Renne et al., 2010; 2011) providing refined estimates for the 40K decay constants, and very significant improvements in precision. Paleozoic and Paleoproterozoic examples will be presented which illustrate the improvements in the accuracy and precision of 40Ar-39Ar ages calculated using the revised decay constants, and discuss the implications for studies that use a combination of U-Pb and 40Ar-39Ar data to constrain the timing and duration of metamorphic, deformation, and mineralisation events. An Excel spreadsheet is available on request that allows recalculation of 40Ar-39Ar ages and uncertainties using the revised parameters of Renne et al. (2010; 2011), provided certain minimum information has been reported with the published ages.