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  • Presentation slides and speaking notes are provided for a presentation that was given online on Wednesday 7th October 2020, 11:00 to 12:00 AEDT time (UTC +11). The presentation coincided with the release of two products; (1) a new web page for the Australian Fundamental Gravity Network (AFGN), and (2) the 2019 Australian National Gravity Grids (eCat Record 133023). Not mentioned as a separate item, the presentation drew heavily on material in the Explanatory Notes for the gravity grids (eCat Record 144233) which was also released on this day. The presentation was pitched at the level of a general audience. It commenced with an introduction to gravity, and how it changes from one place to another in step with different geological units. The subjects of 2-dimensional digital grids and how coloured images are derived from them were then covered as a prelude to later material. The speakers then described first of the two main topics - the Australian Fundamental Gravity Network (AFGN) and its importance when producing the 2019 Australian National Gravity Grids. The AFGN is a series of gravity benchmarks that allow gravity surveys to be linked to the Australian Absolute Gravity Datum 2007 (AAGD07). This makes it possible for the many separate gravity data sets that have been acquired in Australia to be combined into a seamless whole. Gravity data from 1308 ground surveys and 14 blocks of airborne gravity and airborne gravity gradiometry have been combined with offshore gravity data from satellite altimetry to form the 2019 Australian National Gravity Grids. This marks the first time that airborne data have been incorporated into the national gravity grids. It is also the first time that the offshore data have been fully processed alongside the onshore data. Grids of three types of gravity anomalies were produced; Free Air Anomaly (FAA), Complete Bouguer Anomaly (CBA), and De-trended Global Isostatic Residual (DGIR). During the presentation, various comparisons were made illustrating the improvements made with the 2019 grids in comparison with the previous 2016 grids and the benefits of incorporating airborne data into the grids. The gravity grids were produced to assist those involved in geological mapping and exploration, and it is hoped that the new grids will inspire users to revisit their geological interpretations and to aid explorers to identify new opportunities and to more efficiently focus their efforts on prospective ground. The presentation was recorded, and the recording of the presentation is available on demand on the Geoscience Australia YouTube Channel at https://youtu.be/3CyqrqBM0xg. Introductions were made by Marina Costelloe. The event was controlled by Chris Nelson, and the recording was edited by Douglas Warouw. Note that there are some minor differences between the presentation material given here and the presentation seen in the video recording. These changes were made in the interest of clarity and include the removal of “animation” effects and the provision of some additional text. Speaker Biography for Richard Lane; Richard joined Geoscience Australia in 2001 after a career as a mineral and petroleum geophysicist with CRA Exploration / Rio Tinto and as the Program Leader responsible for the development of the TEMPEST AEM system in CRC AMET. As a Senior Geophysicist in the Geophysical Acquisition and Processing Section, he has been evaluating the role of airborne gravity and airborne gravity gradiometry on a national scale. He is an ASEG Gold Medal recipient, a Society of Exploration Geophysicists Honorary Lecturer, and a Distinguished Geoscience Australia Lecturer. Speaker Biography for Phillip Wynne; Phillip has been with GA for over twenty years. In that time, he has been involved in all aspects of regional gravity surveys. He currently oversees gravity surveys conducted by GA and Australian States and Territories and manages the Australian Fundamental Gravity Network.

  • Have you ever wondered what lava looks like when it cools down? This short video introduces rocks from volcanoes and their features using some of the samples in the Geoscience Australia Education Centre. Viewers are shown different types of lava rock, bombs, obsidian and pumice. The video is suitable for middle primary and older students as well as a general audience; it introduces some technical terms and uses samples available for school students to handle during visits to the Centre.

  • This flythrough shows the seafloor bathymetry, cores and canyon names for the Sabrina slope region of East Antarctica. Indigenous names for canyons were proposed following consultation with the Noongar people in Western Australia, the region of Western Australia that was formerly conjugate to the Sabrina margin. Canyon names are as follows: 1. Boongorang Canyon (Blowing in the wind) 2. Manang Canyon (Pool of Water Canyon) 3. Maadjit Canyon (Water Serpent Canyon) 4. Jeffrey Canyon (after Shirley Jeffrey, diatom researcher) 5. Morka Canyon (Winter Canyon) 6. Minang-a Canyon (Whale Canyon)

  • Probabilistic methods applied to infrequent but devastating natural events are intrinsically challenging. For tsunami analyses, a suite of geophysical assessments should be in principle evaluated because of the different causes generating tsunamis (earthquakes, landslides, volcanic activity, meteorological events, asteroid impacts) with varying mean return times. Probabilistic Tsunami Hazard Analyses (PTHAs) are conducted in different areas of the world at global, regional, and local scales with the aim of assessing and mitigating tsunami risk and improving the early warning systems. The PTHAs enhance knowledge of the potential tsunamigenic threat by estimating the probability of exceeding specific characteristics of the tsunami intensities (e.g. run-up or maximum inundation heights) within a certain period of time (exposure time) at given locations (target sites); these estimates can be summarized in hazard maps or hazard curves. This discussion presents a broad overview of PTHA, including: (i) sources and mechanisms of tsunami generation, emphasizing the variety and complexity of the tsunami sources and their generation mechanisms; (ii) developments in modelling the propagation and impact of tsunami waves; (iii) statistical procedures for tsunami hazard estimates that include the associated epistemic and aleatoric uncertainties. Key elements in understanding the potential tsunami hazard are discussed, in light of the rapid development of PTHA methods during the last decade and the globally distributed applications, including the importance of considering multiple sources, their relative intensities, probabilities of occurrence and uncertainties in an integrated and consistent probabilistic framework.

  • <p>Flythrough movie of Bremer Commonwealth Marine Reserve, southwest Western Australia showing bathymetry of Bremer Canyon, Hood Canyon, Henry Canyon and Knob canyon. <p>This research is supported by the National Environmental Science Program (NESP) Marine Biodiversity Hub through Project D1.

  • <p>Bathymetry flythrough of Perth Canyon using data acquired by Schmidt Ocean Institute in 2015 on RV Falkor (University of Western Australia et al.). The flythrough highlights geomorphic features mapped by Geoscience Australia, including landslides, escarpments and bedform fields and biodiversity associated with the canyon (benthic and pelagic). Produced as a science communication product for the Marine Biodiversity Hub (National Environmental Science Program). <p>This research is supported by the National Environmental Science Program (NESP) Marine Biodiversity Hub through Project D1.

  • Understanding disaster risk enables Government, industry and the community to make better decisions on how to prepare for disasters and improve the resilience of communities. Geoscience Australia develops and provides fundamental data and information to understand disaster risk so that we can determine how hazards impact the things that are valuable to us.

  • Audio-visual materials created from OpenQuake training delivered by the Global Earthquake Model held at Geoscience Australia in September 2014.

  • An important part of the management of Australia's marine resources is mapping the geology beneath the sea floor; as part of this work we must understand and mitigate associated environmental impacts. This multimedia product provides background information on marine seismic surveys and the environment, as well as Geoscience Australia's role in environmental mitigation and research. For further information visit http://www.ga.gov.au/about/projects/m.... About the data visualisation: The visualisation of the seismic survey process is representative of a seismic survey, and does not represent any particular survey performed by a particular party. It is not to scale, and is only intended to convey the basic concepts of marine seismic surveys. Production credits: Script: Robin Swindell, Neil Caldwell, Chantelle Farrar, Andrew Carroll, Rachel Przeslawski Production Management: Chantelle Farrar, Neil Caldwell Edit, Cinematography, Sound: Michael O'Rourke 3D Data Visualisation, Animation: Neil Caldwell, Julie Silec Broadcast Design: Julie Silec Scientific Advice: Andrew Carroll, Rachel Przeslawski, Merrie-Ellen Gunning http://www.ga.gov.au Category Science & Technology License Creative Commons Attribution license (reuse allowed)

  • Animation showing Australian Earthquakes since 1964