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.

Abstract for SGA Townsville 2009

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.

Extended abstract version of short abstract accepted for conference presentation GEOCAT# 73701

The Tsunami Data Access Tool (Tsu-DAT) is intended for use by the emergency management community to understand the offshore tsunami hazard for areas of interest around Australia and to access the large database of tsunami waveforms to generate the required input to a detailed tsunami impact assessment for a given community. The offshore tsunami hazard and resultant waveforms are a result of the probabilistic tsunami hazard assessment (PTHA) of Australia (Burbidge2008a). This assessment modelled thousands of synthetic tsunami to estimate the likelihood of a tsunami wave of a given amplitude occurring at an offshore location, defined at the 100 m depth contour. A database of tsunami waveforms at points along the 100 m depth contour around the Australian coast was created. The Tsu-DAT allows users to search this database and extract tsunami waveforms for events of interest. These waveforms are in a format that can be used to drive more detailed models of tsunami inundation and impact for communities of interest.

The first RSTT model for Australia has been developed based on the Australian Seismological Reference Model (AuSREM) that was released in late 2012. The densely-gridded P and S wave distributions of the crust and upper mantle of AuSREM have been simplified and translated into the 7 layer crustal and upper mantle RSTT model. Travel times computed with this RSTT model are evaluated against travel times computed in full 3D through the AuSREM model to assess the impact of the approximations used by RSTT. Location estimates of 5 ground truth earthquakes (GT1, GT2 and GT5) using the global ak135 reference model, the RSTT model and the full 3D travel times are compared. It is found that the RSTT model can reproduce the 3D travel times fairly accurately within its distance of applicability, thereby improving location estimates compared to using a global travel time model like ak135. However the benefit of using RSTT for locating Australian earthquakes is far less than using full 3D travel times, mainly because most stations tend to be further away from the source than the distance of RSTT applicability.

Geoscience Australia has developed an interactive 3D viewer for three national datasets; the new Radiometric Map of Australia (Geoscience Australia 2009b), the Magnetic Anomaly Map of Australia (Geoscience Australia 2004), and the Gravity Anomaly Map of the Australian Region (Geoscience Australia 2008). The interactive virtual globe is based on NASA's open source World Wind Java Software Development Kit (SDK) and provides users with easy and rich access to these three national datasets. Users can view eight different representations of the radiometric map and compare these with the magnetic and gravity anomaly maps and satellite imagery; all draped over a digital elevation model. The full dataset for the three map sets is approximately 55GB (in ER Mapper format), while the compressed full resolution images used in the virtual globe total only 1.6GB and only the data for the geographic region being viewed is downloaded to users computers. This paper addresses the processes for selecting the World Wind application over other solutions, how the data was prepared for online delivery, the development of the 3D Viewer using the Java SDK, issues involving connecting to.

The Capel and Faust basins are located in a frontier part of offshore eastern Australia, about 800 km east of Brisbane in 1300-2500 m of water. Little is known of the basin structures and geological history of this area, which is a continental fragment separated from Australia during the Cretaceous rifting of the Tasman Sea. In 2007 Geoscience Australia acquired 6000km of 2D seismic reflection and refraction data, gravity and magnetics, to begin an assessment of the petroleum prospectivity of these basins. A workflow has been developed to assist the seismic interpreter with feedback from a coherent 3D geology model that is used to predict the gravity response of the basins. This response is harmonized with the observed gravity and modified geological horizons are then returned to the seismic interpreter. An interface between Geoframe and Geomodeller has been optimized to make it very easy to do many iterations of this process, as suits the changing needs of the interpretation team.

Receiver function studies of Northern Sumatra T. Volti and A. Gorbatov Geoscience Australia, GPO Box 378 Canberra ACT 2601 Australia The Northern Sumatra subduction zone is distinguished by the occurrence of the 2004 Sumatra-Andaman megathrust earthquake and has a peculiar subduction of two major bathymetric structures; the Investigator fracture zone and the Wharton fossil ridge. Four stations in Northern Sumatra (BSI, PSI, PPI, GSI) and two stations in Malaysia (KUM and KOM) have been selected to construct migrated images based on receiver functions (RF) in order to study Earth structure and subduction processes in the region. Waveforms from 304 teleseismic earthquakes with Mb >5.5 and a distance range of 30º to 95º recorded from April 2006 to December 2008 were used for the analysis. The number of RF for each station varies from 20 to 192 depending on the signal/noise ratio. The computed RF clearly show pS conversions at major seismic velocity discontinuities associated with the subduction process where the Moho is visible at 5.5, 4, 3.5, and 2 sec for BSI, PSI, PPI, and GSI, respectively. RF for KUM and KOM have only conversions at the Moho near ~4 sec. The subducted slab is visible below Sumatra as a positive amplitude conversion preceded by a negative one, which we interpret as a low-velocity structure above the subducted slab. RF for PSI located at Toba supervolcano reveal pockets of low-velocity zones extending from a ~50 km depth down to the subducted slab. Forward modellings of RF suggest that seismic velocity contrasts can reach ~18% that is in accordance with previous local tomographic studies.

Abstract. Severe wind is one of the major natural hazards in Australia. The component contributors to economic loss in Australia with regards to severe wind are tropical cyclones, thunderstorms and sub-tropical (synoptic) storms. Geoscience Australia's Risk and Impact Analysis Group (RIAG) is developing mathematical models to study a number of natural hazards including wind hazard. This paper discusses wind hazard under current and future climate using RIAG's synoptic wind hazard model. This model can be used in non-cyclonic regions of Australia (Region A in the Australian-New Zealand Wind Loading Standard; AS/NZS 1170.2:2002) where the wind hazard is dominated by synoptic and thunderstorm gust winds.