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Fugitive methane emissions, in particular relating to coal seam gas (CSG),has become an emerging issue in Australia over the last few years. There has been significant controversy in US regarding the magnitude of fugitive emissions during production from unconventional gas wells, with large differences in emissions reported between studies using different measurement approaches. . Preliminary research into a small number of Australia's unconventional fields suggest the average fugitive emissions per well are lower than that found in the US. The primary challenge is that the techniques for quantifying methane leakages are still at an early stage of development. Current methods for the small to medium scale use chamber based approaches or vehicles installed with fixed sampling lines and high precisions gas analysers. These technologies are promising, but generally have not been ground truthed in field conditions against known emission rates to estimate effectiveness. They also have limited application in environments where vehicle access is not possible. The Ginniderra facility is being upgraded to support a methane controlled release experiment in 2015. This will enable testing of and verifying methods and technologies for measuring and quantifying methane emissions. To address the absence of suitable techniques for emmission measurement at medium scales, several BOREAL lasers will be deployed which work at scales of 20-1000 m. It is also envisaged airborne techniques utilising laser and hyperspectral will be deployed, along with tomography work utilising multiple concurrent concentration measurements.
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Single-copounds carbon isotops of Precambrian eviporates.
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When considering structural design with regard to wind loading, the Australian building code through the Australia/New Zealand Wind Actions Standard (AS/NZS 1170.2, 2002) as well as the wind engineering community in general, relies to a significant extent on the peak wind gust speed observations collected over more than 60 years by the Bureau of Meteorology (BoM). The wind-loading performance of our infrastructure (resilience) is based primarily on the Dines anemometer interpretation of the peak gust wind speed. In the early 1990's BoM commenced a program to replace the aging pressure tube Dines anemometer with the Synchrotac and Almos cup anemometers. This paper presents the results of a reanalysis of the current BoM peak wind gust database for the non-cyclonic region (Region A) of AS/NZS 1170.2 (2002). We compares estimates of the 500-year RP peak wind gust hazard magnitude derived of varying observing record lengths obtained from 31 "Region A" BoM sites. Region A was considered for this initial study as record length would contain a significant number of extreme events (synoptic or thunderstorm) over decadal time scales (i.e. extremes not dominated by one or two tropical cyclone events). To isolate the issue of anemometer replacement, only wind stations located at airports (consistent exposure) and with more than 30 years of record were considered. The methodology was formulated to explore the consistency of peak wind gust measurements due to issues surrounding equipment upgrading. Comparison of results indicated that the recent period (1990-2006) appears to have a reduction in significant events (13 of 31 sites have a mean 500 year RP below the 95% confidence limit for the 500 year RP estimate using the total record). Future plans are to calibrate some existing Dines instruments in-situ in an effort to provide sufficient information to fully specify the dynamic response over the range of operating conditions
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A depth to magnetic basement map has been produced for the Gawler-Curnamona region of South Australia. The map combines depth to magnetic source estimates with outcrop, drill hole and seismic data. The spectral domain method of analysing the slope of straight line segments in the power spectrum was used to produce the majority of the magnetic source depth estimates. The spectral domain method was incorporated into a semi-automated in-house software package to rapidly produce the regional scale map. The reliability of the depth to magnetic basement map is heavily dependent on the reliability of the depth to magnetic source estimation methods. There are a number of factors that can lead to errors, such as data quality and wrongly assigning magnetic sources to the cover or basement. The spectral domain method tends to slightly over estimate depths, however the average absolute errors are less than %30 when compared to known depths which is considered reasonable for the production of this type of regional scale map. The map delineates large areas of prospective Gawler Craton and Curnamona Province basement beneath less than 300 m of cover material, providing a useful tool for the mineral explorer. The map also delineates large areas under thick sequences of sediments, greater than 1000 m, which may prove of interest for the hydrocarbon explorer or act as a thermal blanket for the geothermal explorer.
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The seismicity of the Australian continent is low to moderate by world standards. However, the seismic risk is much higher for some types of Australian infrastructure due to an incompatibility of structural vulnerability with local earthquake hazard. The earthquake risk in many regional neighbours is even higher due to high hazard, community exposure and vulnerability. The Risk and Impact Analysis Group is a multidisciplinary team at Geoscience Australia that is actively engaged in research to better understand earthquake risk in Australia and to assist agencies in neighbouring countries develop similar knowledge. In this presentation aspects of this work will be described with a particular focus on engineering vulnerability, post disaster information capture and how both can point to effective mitigation options. Risk is the combination of several components (hazard, exposure, vulnerability and impact) that combine to provide measures that can be very useful for decision makers. Vulnerability is the key link that translates hazard exposure to consequence. Vulnerability is typically expressed in physical terms but includes interdependent utility system vulnerability, economic activity vulnerability and the social vulnerability of communities. All four vulnerability types have been the subject of research at GA but the physical vulnerability is the primary link to the others. Vulnerability research for Australian infrastructure will be presented in the context of a holistic risk framework. Furthermore, the work in the Philippines to develop a first order national suite of models will also be presented. Post disaster survey data is invaluable for understanding the nature of asset vulnerability, developing empirical models and validating analytical models based on structural models. Geoscience Australia has developed a range of tools to assist with damage capture that have been used for several hazard types, including earthquake. Tools include portable street view imagery capture, GPS technology and hand-held computers. Experience with the application of these tools and the information that has been derived will be described along with current activity to improve their utility.
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The Mount Lofty and Flinders Ranges of South Australia are bound on the east and the west by reverse faults that thrust Proterozoic and/or Cambrian basement rocks over Quaternary sediment. These faults range from a few tens to almost one hundred kilometres in length and tend to be spaced significantly less than a fault length apart. In the few instances where the thickness of overthrust sediment can be estimated, total neotectonic throws are in the order of 100-200 m. Slip rates on individual faults range from 0.02-0.17 mm/a, with one unconfirmed estimate as high as 0.7 mm/a. Taking into account the intermittent nature of faulting in Australia, it has been suggested that 30-50% of the present-day elevation of the Flinders and Mount Lofty Ranges relative to adjacent piedmonts has developed in the last 5 Ma. Uplifted last interglacial shorelines (ca. 120 ka) along the southern coastline of the Mount Lofty Ranges indicate that deformation is ongoing. Palaeoseismological investigations provide important insight into the characteristics of the large earthquakes responsible for deformation events. Single event displacements of 1.8 m have been measured on the Williamstown-Meadows Fault and the Alma Fault, with the former relating to a surface rupture length of a least 25 km. Further to the south in Adelaide's eastern suburbs, a 5 km section of scarp, potentially relating to a single event slip on the Eden-Burnside Fault, is preserved in ca. 120 ka sediments. Where the Eden-Burnside Fault meets the coast at Port Stanvac 20 kilometres south, the last interglacial shoreline is uplifted by 2 m relative to its expected position. At Normanville, on the uplifted side of the Willunga Fault, the last interglacial shoreline is over 10 m above its expected position, implying perhaps five or more surface rupturing events in the last ca. 120 ka on this >50 km long fault. On the eastern range front, a very large single event displacement of 7 m is inferred on the 54 km long Milendella Fault, and the 79 km long Encounter Fault displaces last interglacial shorelines by up to 11 m. There is abundant evidence for large surface-breaking earthquakes on many faults within 100 km of the Adelaide CBD. Slip rates are low by plate margin standards, implying a low rate of recurrence for M7+ events on individual faults (perhaps 10,000 years or more). However, a proximal moderate-sized event or even a large event at distance has the potential to cause significant damage to Adelaide, particularly given its construction types and local site conditions.
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Vertical geochemical profiling of the marine Toolebuc Formation, Eromanga Basin - implications for shale gas/oil potential The regionally extensive, marine, mid-Cretaceous (Albian) Toolebuc Formation, Eromanga Basin hosts one of Australia's most prolific potential source rocks. However, its general low thermal maturity precludes pervasive petroleum generation, although regions of high heat flow and/or deeper burial may make it attractive for unconventional (shale gas and shale oil) hydrocarbon exploration. Previous studies have provided a good understanding of the geographic distribution of the marine organic matter in the Toolebuc Formation where total organic carbon (TOC) contents range to over 20% with approx. half being of labile carbon and convertible to gas and oil. This study focuses on the vertical profiling, at the decimetre to metre scale, of the organic and inorganic geochemical fingerprints within the Toolebuc Formation with a view to quantify fluctuations in the depositional environment and mode of preservation of the organic matter and how these factors influence hydrocarbon generation thresholds. The Toolebuc Formation from three wells, Julia Creek-2 and Wallimbulla-2 and -3, was sampled over an interval from 172 to 360m depth. The total core length was 27m from which 60 samples were selected. Cores from the underlying Wallumbilla Formation (11 samples over 13m) and the overlying Allaru Mudstone (3 samples) completed the sample set. Bulk geochemical analyses included %TOC, %carbonate, %total S, -15N kerogen, -13C kerogen, -13C carbonate, -18O carbonate, and major, minor and tracer elements and quantitative mineralogy. More detailed organic geochemical analyses involved molecular fossils (saturated and aromatic hydrocarbons, and metalloporphyrins), compound specific carbon isotopes of n-alkanes, pyrolysis-gas chromatography and compositional kinetics. etc.
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The Paterson AEM survey was flown over the Paterson Orogen, the eastern Pilbara Craton and the on-lapping Officer and Canning Basins in NW Western Australia between September 2007 and October 2008 as part of the Commonwealth Government's Onshore Energy Security Program. The survey was designed to provide pre-competitive data for enhancing uranium and other mineral exploration. Flight lines were at a variety of spacings from 6, 2 and 1 km to 200 m targeting known deposits and other covered highly prospective rocks for a total area of 45,330 km2. The survey data has afforded new insights into the Paleozoic paleotopography of the region which is blanketed by regolith including Phanerozoic sediments including Permian glaciogene, Mesozoic and Cenozoic sediments. These insights have major implications for mineral prospectivity.
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Magnetotelluric (MT) data have been acquired in 2008 and 2009 at 40 broadband (0:01 s to 500 s) and 12 long-period (10 s to 10 000 s) sites along the east-west deep seismic reflection transect of northern Eyre Peninsula, South Australia. The MT survey is a joint project between the University of Adelaide and Geoscience Australia and is funded by the Australian Government as part of the Onshore Energy Security Program. Long-period sites are spaced 20 km apart and broadband sites infill this spacing to 10 km with also some 5 km spacing. This ensures sufficient coverage to map the upper crustal to upper mantle structures beneath northern Eyre Peninsula.
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Abstract # : 1479734 Paper # : GP43B-1142 Session : GP43B Potential-field and EM methods for geologic problems of the mid and upper crust Developments for 3D gravity and magnetic modeling in spherical coordinates Richard Lane - Geoscience Australia - rjllane@gmail.com Qing Liang - China University of Geosciences (Wuhan) - qingliang.cug@gmail.com Chao Chen - China University of Geosciences (Wuhan) - chenchao@cug.edu.cn Yaoguo Li - Colorado School of Mines - ygli@mines.edu At Geoscience Australia (GA), Australia's Commonwealth Government geoscientific agency, we perform gravity and magnetic modeling at a range of scales, from broad regional crustal studies with thousands of kilometer lateral extent and tens of kilometer vertical extent, to detailed local studies with kilometer or less lateral extent and meters to hundreds of meters vertical extent. To achieve greater integration and coherence, and to better understand the geological significance of this work, we are investing in a number of development projects; * Spherical coordinate gravity and magnetic modeling, * Modeling using High Performance Computing facilities, * Utilizing rock property data as an input into the modeling and interpretation of gravity and magnetic data, * Better management of geoscience data and models, and * Visualization of spatial data in a Virtual Globe format. In collaboration with the Colorado School of Mines (CSM) and the China University of Geosciences (CUG), we are developing a capability to model gravity and magnetic data in a spherical coordinate framework. This will provide more accurate calculations and permit us to integrate the results into a single framework that more realistically reflects the shape of the Earth. Modeling gravity and magnetic data in a spherical coordinate framework is far more compute intensive than is the case when performing the corresponding calculations in a Cartesian (rectangular) coordinate framework. To reduce the time required to perform the calculations in a spherical coordinate framework, we will be deploying the modeling software on the National Computational Infrastructure (NCI) High Performance Computing (HPC) facility at the Australian National University (ANU). This will also streamline the management of these software relative to the other main option of establishing and maintaining HPC facilities in-house. We are a participant in the Deep Exploration Technologies Cooperative Research Centre (DET CRC). In combination with this involvement, we are expanding our support for systematic management of rock property data, and developing a better understanding of how these data can be used to provide constraints for the modeling work. We are also using the opportunities afforded through the DET CRC to make progress with documentation and standardization of data storage and transfer formats so that the tasks of management, discovery and delivery of this information to users are simplified and made more efficient. To provide the foundations of integration and analysis of information in a spatial context, we are utilizing and customizing 3D visualization software using a Virtual Globe application, NASA World Wind. This will permit us to view the full range of information types at global to local scales in a realistic coordinate framework. Together, these various development activities will play an important role in the on-going effort by Geoscience Australia to add value to the potential field, rock property, and geological information that we possess. We will then be better able to understand the geology of the Australian region and use this knowledge in a range of applications, including mineral and energy exploration, natural hazard mitigation, and groundwater management.