One of the main outputs of the Earthquake Hazard project at Geoscience Australia is the national earthquake hazard map. The map is one of the key components of Australia's earthquake loading standard, AS1170.4. One of the important inputs to the map is the rate at which earthquakes occur in various parts of the continent. This is a function of the strain rate, or the rate of deformation, currently being experienced in different parts of Australia. This paper presents two contrasting methods of estimating the strain rate, and thus the seismicity, using the latest results from the seismology and geodynamic modelling programs within the project. The first method is based on a fairly traditional statistical analysis of an updated catalogue of Australian earthquakes. Strain rates, where measurable, were in the range of 10-16s-1 to around 10-18s-1 and were highly variable across the continent. By contrast, the second method uses a geodynamic numerical model of the Australian plate to determine its rate of deformation. This model predicted a somewhat more uniform strain rate of around 10-17s-1 across the continent. The uniformity of the true distribution of long term strain rate in Australia is likely to be somewhere between these two extremes but is probably of about this magnitude. In addition, this presentation will also give an overview of how this kind of work could be incorporated into future versions of the national earthquake hazard map in both the short and long term.

This dataset contains species identifications of crinoids collected during survey SOL4934 (R.V. Solander, 27 August - 24 September, 2009). Animals were collected from the Joseph Bonaparte Gulf with a benthic sled. Specimens were lodged at Museum of Victoria on the 19 April 2010. Species-level identifications were undertaken by Kate Naughton at the Museum of Victoria and were delivered to Geoscience Australia in December 2010. See GA Record 2010/09 for further details on survey methods and specimen acquisition. Data is presented here exactly as delivered by the taxonomist, and Geoscience Australia is unable to verify the accuracy of the taxonomic identifications.

Project Y4 Final Report Parts I & II January 2005 July 2008 Concepts to targets:a scale integrated mineral systems study of the Eastern Yilgarn Craton

The purpose of this paper is to investigate and quantify the accuracy with which hydrological signals in the Murray-Darling Basin, southeast Australia can be estimated from GRACE. We assessed the extent to which the Earth's major geophysical processes contaminate the gravitational signals in the Basin. Eighteen of the world's largest geophysical processes which generate major gravitational signals (e.g. melting of the Greenland icesheet, hydrology in the Amazon Basin) were simulated and the proportion of the simulated signal detected in the Murray - Darling Basin was calculated. The sum of the cumulative effects revealed a maximum of ~4 mm (equivalent water height) of spurious signal was detected within the Murray - Darling Basin; a magnitude smaller than the uncertainty of the basin-scale estimates of changes in total water storage. Thus, GRACE products can be used to monitor broad scale hydrologic trends and variability in the Murray-Darling Basin without the need to account for contamination of the estimates from external geophysical sources.

During 2008 and 2009, and under the Australian Government's Onshore Energy Security Initiative, Geoscience Australia acquired airborne electromagnetic (AEM) data over the Pine Creek Orogen of the Northern Territory. The survey area was split into three areas for acquisition. VTEM data was acquired in the Kombolgie area east of Kakadu National Park between August and November 2008. TEMPEST data was acquired west of Kakadu National Park with the area split in two to facilitate the use of two aircraft: the Woolner Granite area in the north (this data set) was acquired between October and December 2008; and the Rum Jungle area adjoining to the south, was acquired between October 2008 and May 2009. The main purpose of the surveys was to provide additional geophysical/geological context for unconformity style uranium mineral systems and thereby promote related exploration. The survey data will also provide information on depth to Proterozoic/Archean basement, which is of general interest to explorers, and will be used as an input into ground water studues in the region.

The occurrence of the Indian Ocean Tsunami on 26 December, 2004 has raised concern about the difficulty in determining appropriate tsunami mitigation measures in Australia, due to the lack of information on the tsunami threat. A first step in the development of such measures is a tsunami hazard assessment, which gives an indication of which areas of coastline are most likely to experience tsunami, and how likely such events are. Here we present the results of a probabilistic tsunami hazard assessment for Western Australia (WA). Compared to other parts of Australia, the WA coastline experiences a relatively high frequency of tsunami occurrence. This hazard is due to earthquakes along the Sunda Arc, south of Indonesia. Our work shows that large earthquakes offshore of Java and Sumba are likely to be a greater threat to WA than those offshore of Sumatra or elsewhere in Indonesia. A magnitude 9 earthquake offshore of the Indonesian islands of Java or Sumba has the potential to significantly impact a large part of the West Australian coastline. The level of hazard varies along the coast, but is highest along the coast from Carnarvon to Dampier. Tsunami generated by other sources (e.g. large intra-plate events, volcanoes, landslides and asteroids) were not considered in this study, which limits our hazard assessment to recurrence times of 2000 years or less.

This report outlines the level survey completed during the visit to Betio Island, the Republic of Kiribati in February / March 2009. This is the third EDM Height Traversing levelling survey of the deep bench mark array in the Republic of Kiribati. The 2009 survey is a repeat survey. On nine previous occasions, from 1992 to 2004 the Kiribati level survey was performed by the National Tidal Centre (NTC) using the Precise Differential Levelling technique. This project is sponsored by the Australian Agency for International Development (AusAID), managed by the Bureau of Meteorology (BOM) and supported by the National Geospatial Reference Systems Project (NGRS), Geospatial Earth Monitoring Division, GEOSCIENCE AUSTRALIA.

This report outlines the level survey completed during the visit to Majuro Atoll, Marshall Islands during 27 March to 4 April, 2009. This is the third EDM Height Traversing levelling survey of the deep bench mark array in Majuro Atoll, Marshall Islands. This is a repeat survey. On eight previous occasions, from 1993 to February 2003, the Marshall Islands level survey was performed by the National Tidal Centre (NTC) using the Precise Differential Levelling technique. This project is sponsored by the Australian Agency for International Development (AusAID), managed by the Bureau of Meteorology (BOM) and supported by the National Geospatial Reference Systems Project (NGRS), Geospatial Earth Monitoring Division, GEOSCIENCE AUSTRALIA.

This report outlines the level survey completed during the visit to Manus Island, Papua New Guinea (PNG) from 8 - 12 June 2009. Precise Differential Levelling surveys were performed on previous occasions, from 1994 to 2003 by NTC and the survey in January 2006 was a comparison between the precise levelling and EDM height traversing technique. This is the third EDM Height Traversing levelling survey of the deep bench mark array in Manus Island, PNG. The previous levelling surveys using this technique were performed in January 2006 and August 2007. This project is sponsored by the Australian Agency for International Development (AusAID), managed by the Bureau of Meteorology (BOM) and supported by the National Geospatial Reference Systems Project (NGRS), Geospatial Earth Monitoring Division, GEOSCIENCE AUSTRALIA.

This report outlines the level survey completed during the visit to Honiara, Solomon Islands during 12 - 19 May 2009. Precise Differential Levelling surveys were performed on four previous occasions, from August 1994 to March 1999 by NTC. This is the second EDM Height Traversing levelling survey of the deep bench mark array in Honiara, Solomon Islands. The previous levelling survey was performed in August 2007 by Geoscience Australia and SOPAC. This project is sponsored by the Australian Agency for International Development (AusAID), managed by the Bureau of Meteorology (BOM) and supported by the National Geospatial Reference Systems Project (NGRS), Geospatial Earth Monitoring Division, GEOSCIENCE AUSTRALIA.