Earthquake hazard was not fully recognised in Australian building design until the mid-1990's. This oversight has resulted in a legacy of vulnerable buildings that can be readily damaged in moderate to severe Australian earthquakes. In particular, older unreinforced masonry buildings are particularly vulnerable and very common in the centres of our large cities and towns with significant heritage value. What can be done to cost-effectively address the risk they represent to people in the community and to protect these valued assets from future damaging earthquakes? With a focus on the Heritage town of York and the state capital of Melbourne, strategies have been examined as to effectiveness which have included a virtual retrofit to progressively reduce damage, injury, economic losses and emergency management logistics. Communication products derived from this work are described and initiatives to apply them in other Australian communities highlighted.

Geoscience Australia is increasingly looking to quantify the impact and value of the scientific work that it undertakes. Quantifying impact helps to demonstrate the return on investment from expenditure of government funds in applying geoscience to Australia's most important challenges. Recent analysis has quantified the economic and social benefits arising from precompetitive geoscience under Exploring for the Future, an Australian Government program led by Geoscience Australia that is dedicated to exploring Australia's resource potential and boosting investment. This analysis used the Impact Pathway approach to collect data and information that provides evidence of project and program impacts. The analysis demonstrates that Exploring for the Future is likely to return hundreds of dollars to the Australian economy for every dollar spent on the program. Additional modelling using REMPLAN online analytical tools helps to quantify economic and employment benefits in regional Australia. These approaches to impact assessment are also being adopted across Geoscience Australia in areas ranging from satellite Earth observation to earthquake and tsunami hazard and risk.

For the first time in Australia, ground gravity, airborne gravity/gravity gradiometry, and satellite gravity observations have been combined to produce a series of National Gravity Grids covering an area more than twice the size of Australia. This involved the combination of observations made on the land, in the air, and by satellite - more than 1,800 ground gravity surveys, 14 airborne gravity and gravity gradiometry surveys, and satellite gravity observations. Underpinning this accomplishment is the Australian Fundamental Gravity Network - a series of gravity benchmarks that allow the joining of gravity data into a seamless whole. This presentation will discuss both the utility of the network and how it feeds into the production of the grids, plus the process of creating the national scale grids using such varied sources of gravity data.

Hydrogen for energy storage and transport is a key part of the energy transition. Caverns in salt formations can provide high integrity and large-scale storage (>200 GWh). Australia has several basins with thick salt in the subsurface that are prospective for underground hydrogen storage and Geoscience Australia's archive of digital data and physical samples is a crucial resource in assessing these deposits and finding more. New models for the deposition of giant salt deposits, new technologies and the new energy landscape make salt and hydrogen an exciting research frontier.

Australia has a vast and highly dynamic coastline of over 30,000 kilometres with many unique environments: sandy beaches, rocky cliffs, muddy tidal flats, and mangroves. Until recently, this scale and complexity has meant that many of Australia's coastal environments have been poorly and inconsistently mapped, particularly in dynamic or remote regions where accurate survey data can be extremely challenging and costly to obtain. In recent years, however, satellites orbiting our planet have provided a new and powerful source of information about Australia's coast and how it has changed over recent decades. Digital Earth Australia is a government platform that prepares these vast volumes of satellite data and makes it available to governments and industry for easy use. This talk will showcase how new and innovative analysis techniques can be applied to petabytes of DEA satellite data to better understand and monitor Australia's vast coastal zone from space: from using the rise and fall of the tide to map the 3D shape of Australia's coast, to track how our coastline has shifted and changed over the past three decades in unprecedented scale and detail. We will demonstrate how these freely available coastal products and tools developed by Digital Earth Australia can be used by scientists, managers, policymakers and the general public to provide new information to help maintain and protect Australia's iconic shores for future generations.

One annoying geodetic variable is a treasure trove of information to meteorologists. This talk will focus on a project in partnership with the BoM, RMIT and FrontierSI turned our estimates of the tropospheric delay in our GPS analysis into useful information for weather forecasting systems. The system works by measuring the time it takes GPS signals from satellites to reach ground receivers. Signals can be slightly delayed by moisture in the troposphere, causing what's known as a zenith total delay, so scientists measure this delay to assess air moisture While the technology could be applied almost anywhere, it is particularly valuable in a sparsely populated country like Australia where there is a lack of ground-based meteorological observation stations. Atmospheric water vapour is highly variable and non-linear in nature, yet it is important for accurate weather forecasting of storms. Having a direct observation from GPS provides an exciting opportunity for near and real-time weather forecasting systems.

Exploring for the Future is an Australian Government program led by Geoscience Australia that aims to drive investment in the resources and agricultural sectors by providing industry and land and water managers with pre-competitive data about potential mineral, energy and groundwater resources. The Australian Government invested $100 million in the first phase of the Exploring for the Future program in 2016. In June 2020, the Australian Government announced a $125 million extension and expansion of the program, bringing their total investment to $225 million to date. Exploring for the Future is building on Geoscience Australia's deep domain knowledge to generate new science and challenge the frontiers of resource exploration. Eight new projects will include the southern half of the continent, with a focus on two potentially resource-rich corridors that stretch across the country. Unlocking these new resource corridors will provide ongoing economic and employment growth across a wide range of regional areas.

Compilation of age and endowment data on volcanic-hosted massive sulfide (VHMS), porphyry copper, orthomagmatic nickel, orogenic gold, granite-related rare metal and pegmatite deposits (nearly 1200 deposits from 21 mineral provinces) indicate that metallogenic patterns change over time. For much of Earth’s history, the metallogenesis of convergent margins is marked by a relatively systematic temporal progression of deposits, the convergent margin metallogenic cycle (CMMC): VHMS, calc-alkalic porphyry copper and orthomagmatic nickel → orogenic gold → alkalic porphyry copper, granite-related rare metal and pegmatite. Typically CMMCs last 70-170 Myr, and the progression appears to be related to the convergent margin tectonic cycle (Collins and Richards, 2008). Prior to ~3100 Ma, however, CMMCs are not recognised. Rather, these old mineral provinces are characterised by long metallogenic histories (400-500 Myr) with an irregular distribution of deposits. The Mesoarchean to Mesoproterozoic is characterised mostly by mineral provinces with short (80-150 Myr) metallogenic histories and a single CMMC. Between 1900 Ma and 1800 Ma, however, some mineral provinces (e.g. Trans-Hudson and Sveccofennian) are characterised by multiple CMMCs, with total metallogenic histories that last up to 200 Myr. Paleoproterozoic provinces with multiple CMMCs formed by the consumption of internal seas, whereas mineral provinces on outward-facing convergent margin typically have only one CMMC. After ~800 Ma, convergent margins are mostly long-lived (290-480 Myr) and are characterised by multiple CMMCs with complex metallogenic histories. The changes in the metallogenesis of convergent margins reflect changes in tectonic processes through time. Prior to 3100 Ma, stagnant lid tectonics, which did not involve subduction, resulted in the formation of oceanic plateaus with irregular periods of mineralisation. After the initiation of subduction at ~3100 Ma, the style of metallogenesis changed. The dominance of provinces with a single CMMC from 3100 to 800 Ma suggests that convergent margins were unstable and could be shut down easily. This is consistent with models of shallow-break-off subduction whereby the subducting slab breaks off at shallow levels due to the lower plate strength in the Archean and the early part of the Proterozoic. When the slab breaks off, the subduction system shuts down and produces a single CMMC. Only in cases where factors such as closure of internal seas force continued subduction do multiple CMMCs occur. The change to longer metallogenic histories and multiple CMMCs at ~800 Ma is likely the consequence of the cooling of the mantle, which increases plate strength, allowing subduction of cold slabs deeper into the mantle and more stable convergence: continuous ridge push and the density of oceanic crust causes re-initiated of subduction further outboard rather than complete termination of subduction when the convergent margin is perturbed by the accretion of an exotic block or other tectonic event. Subduction only terminates upon collision of two major crustal blocks. As a consequence, the metallogenic history or geological young convergent margins is long with multiple CMMIs and/or complex temporal interleaving of deposit types.

Geoscience Australia currently retains the Analysis Centre Coordinator role for the International GNSS Service (IGS). The IGS Analysis Centre Coordinator (ACC) has overall responsibility for generating the main official IGS combined products. Currently, there are three IGS product lines for GNSS satellite orbits and clocks, namely the IGS Final, the IGS Rapid, and the IGS Ultra-rapid products, each with different accuracies and latencies. The IGS is a key operational agency for supporting multi-constellation GNSS operations enabling governments, academia and industry to provide highest quality positioning services. This coordination role is fundamental to the Positioning Australia program and specifically for the Ginan Analysis Centre Software to transition into an IGS endorsed globally recognised Analysis Centre. This talk introduces the GA's role in the IGS Analysis Centre Coordination and the relevance to the Positioning Australia and generally Australia operating a GNSS Analysis Centre with an operational Ginan analysis centre software as part of the GA Strategy 2028 Creating a Location-Enabled Australia.

Geoscience Australia has undertaken a regional seismic mapping study of the offshore Otway Basin extending across the explored inner basin to the frontier deep-water region. Seismic interpretation covers over 18,000 line-km of new and reprocessed data acquired in the 2020 Otway Basin seismic program, over 40,000 line-km of legacy 2D seismic data and GA’s new 2023 Otway 3D post-stack Mega Merge seismic dataset. This work provides a new perspective on regional structural architecture and basin evolution and has important implications for hydrocarbon prospectivity of this region. This seminar was two short talks centring on the Otway Basin. <u>Post-stack 3D merging to fast-track regional interpretation - offshore Otway Basin case study, presented by Merrie-Ellen Gunning</u> This case study was to produce a regularised and seamless 3D dataset of the highest possible quality, for the offshore Otway Basin, within two-months. The input migrated volumes varied by data extent, migration methodology, angle range and grid orientation. Fourteen input volumes totalling 8,092 km2 were post-stack merged and processed to produce a continuous and consistent volume, enabling more efficient and effective interpretation of the region. The surveys were regularised onto a common grid, optimised for structural trend, prior to survey matching. A mis-tie analysis algorithm, applied over a time window optimised for interpretation of key events, was used to derive corrections for timing, phase and amplitude, using a reference. This was followed by time-variant spectral and amplitude matching to improve continuity between volumes. Additional enhancements including noise removal and lateral amplitude scaling were also applied. The final merged volume offers significant uplift over the inputs, providing better imaging of structure and events and dramatically improving the efficiency and quality of interpretation. This enables rapid reconnaissance of the area by explorers. <u>Structural architecture of the offshore Otway Basin presented by Chris Nicholson</u> We present new basin-scale isochore maps that show the distribution of the Cretaceous depocentres. Maps for the Lower Cretaceous Crayfish and Eumeralla supersequences, together with those recently published for the Upper Cretaceous Shipwreck and Sherbrook Supersequences, completes the set of isochore maps for the main tectonostratigraphic basin intervals. Mapping of basement involved faults has revealed structural fabrics that have influenced depocentre development. The tectonostratigraphic development of depocentres and maps of deep crustal units delineate crustal thinning trends related to late Cretaceous extension phases. This work highlights the need to review and update structural elements. For example, the boundary between the Otway and Sorell basins is now geologically constrained. The refinements to the tectonostratigraphic evolution of the Otway Basin presented here have important implications for the distribution and potential maturity of petroleum systems, especially with regard to heat flow associated with crustal extension.