Prior to the development of Australian-specific magnitude formulae, the 1935 magnitude corrections by Charles Richter – originally developed for southern California – was almost exclusively used to calculate earthquake magnitudes throughout Australia prior to the 1990s. Due to the difference in ground-motion attenuation between southern California and much of Australia, many historical earthquake magnitudes are likely to be overestimated in the Australian earthquake catalogue. A method has been developed that corrects local magnitudes using the difference between the original (inappropriate) magnitude corrections and the Australian-specific corrections at a distance determined by the nearest recording station likely to have recorded the earthquake. These corrections have reduced the rates of local magnitudes of 4.5 in the historical catalogue by about 30% since 1900, while the number of magnitude 5.0 earthquakes has reduced by about 60% in the same time period. The reduction in the number of moderate-to-large-magnitude earthquakes over the instrumental period yields long-term earthquake rates that are more consistent with present-day rates, since the development of Australian-specific magnitude formulae. The adjustment of historical earthquake magnitudes is important for seismic hazard assessments, which assume a Poisson distribution of earthquakes in space and time.

Geoscience Australia has produced an Atlas of Australian earthquake scenarios (the Atlas) to support planning and preparedness operations for emergency management agencies. The Atlas provides earthquake scenarios represent realistic “worst-case” events that may impact population centres around Australia. Such scenarios may also support seismic risk assessments for critical infrastructure assets to inform remediation actions that could be taken to improve resilience to rare seismic events in Australia. The Atlas of seismic scenarios uses the underlying science and data of the 2018 National Seismic Hazard Assessment (NSHA18) to identify the magnitudes and epicentre locations of these hypothetical earthquakes. Locations and magnitudes of earthquake scenarios are based upon deaggregation of the NSHA18 hazard model. The USGS ShakeMap software is used to produce ground motion intensity fields with the shaking levels being modified by seismic site conditions mapped at a national scale. Fault sources are incorporated into the Atlas where the magnitude of a given scenario exceeds a threshold magnitude of 6.0 and where the rupture length is likely to be longer than 10 km. If a scenario earthquake is located near a known fault within the Australian Neotectonic Features database, a partial or full-length rupture is modelled along the mapped fault. The Atlas generated two scenarios for each of the160 localities across Australia. The scenarios are based on some of the most likely earthquake magnitude-distance combinations estimated at each site. Output products include shaking contours for a range of intensity measures, including peak acceleration and velocity, as well as response spectral acceleration for 0.3, 1.0 and 3.0 seconds. Also included are raster images and the associated metadata used for generating the scenarios.

A review of mineral exploration trends, activities and discoveries in Australia in 2020

This petroleum systems summary report provides a compilation of the current understanding of petroleum systems for the South Nicholson Basin and Isa Superbasin region. The contents of this report are also available via the Geoscience Australia Portal at https://portal.ga.gov.au/, called The Petroleum Systems Summary Assessment Tool (Edwards et al., 2020). Three summaries have been developed as part of the Exploring for the Future (EFTF) program (Czarnota et al., 2020); the McArthur Basin, the Canning Basin, and a combined summary of the South Nicholson Basin and Isa Superbasin region. The petroleum systems summary reports aim to facilitate exploration by summarizing key datasets related to conventional and unconventional hydrocarbon exploration, enabling a quick, high-level assessment the hydrocarbon prospectivity of the region.

The annual offshore petroleum exploration acreage release is part of the government’s strategy to promote offshore oil and gas exploration. Each year, the government invites companies to bid for the opportunity to invest in oil and gas exploration in Australian waters. The 21 areas shown have been nominated by petroleum industry stakeholders to be considered for the 2021 acreage release. Areas nominated for release will not receive endorsement from government until submissions resulting from a public consultation process can be considered. This publication does not indicate a commitment to a particular course of action.

Australia has been, and continues to be, a leader in isotope geochronology and geochemistry. While new isotopic data is being produced with ever increasing pace and diversity, there is also a rich legacy of existing high-quality age and isotopic data, most of which have been dispersed across a multitude of journal papers, reports and theses. Where compilations of isotopic data exist, they tend to have been undertaken at variable geographic scale, with variable purpose, format, styles, levels of detail and completeness. Consequently, it has been difficult to visualise or interrogate the collective value of age and isotopic data at continental-scale. Age and isotopic patterns at continental scale can provide intriguing insights into the temporal and chemical evolution of the continent (Fraser et al, 2020). As national custodian of geoscience data, Geoscience Australia has addressed this challenge by developing an Isotopic Atlas of Australia, which currently (as of November 2020) consists of national-scale coverages of four widely-used age and isotopic data-types: 4008 U-Pb mineral ages from magmatic, metamorphic and sedimentary rocks 2651 Sm-Nd whole-rock analyses, primarily of granites and felsic volcanics 5696 Lu-Hf (136 samples) and 553 O-isotope (24 samples) analyses of zircon 1522 Pb-Pb analyses of ores and ore-related minerals These isotopic coverages are now freely available as web-services for use and download from the GA Portal. While there is more legacy data to be added, and a never-ending stream of new data constantly emerging, the provision of these national coverages with consistent classification and attribution provides a range of benefits: vastly reduces duplication of effort in compiling bespoke datasets for specific regions or use-cases data density is sufficient to reveal meaningful temporal and spatial patterns a guide to the existence and source of data in areas of interest, and of major data gaps to be addressed in future work facilitates production of thematic maps from subsets of data. For example, a magmatic age map, or K-Ar mica cooling age map sample metadata such as lithology and stratigraphic unit is associated with each isotopic result, allowing for further filtering, subsetting and interpretation. The Isotopic Atlas of Australia will continue to develop via the addition of both new and legacy data to existing coverages, and by the addition of new data coverages from a wider range of isotopic systems and a wider range of geological sample media (e.g. soil, regolith and groundwater).

This synthesis of geophysical results for Australia is designed to provide an summary of the character of the Australian continent through the extensive information available at the continental scale. We present a broad range of geophysical attributes for the continent nation. We also endeavour to examine the relationships between different fields, and their relations to known resources. The work represents part of a continuing collaboration between the Research School of Earth Sciences at The Australian National University and Geoscience Australia with the objective of bringing together all aspects of the structure of Australia in convenient forms. The results build on the extensive data bases assembled at Geoscience Australia, particularly for potential fields, supplemented by the full range of seismological information mostly from the Australian National University. The book builds in part on the AUSREM project sponsored by the AuScope infrastructure organisation to develop a 3-D representation of seismological structure beneath the Australian region. The diverse and extensive geophysical data sets available for Australia in part reflect the poor outcrop of bedrock geology for this ancient weathered continent and the economic importance of this geology to the Australian economy through its resource potential. Geophysics provides an important way to examine the structures that lie beneath the cover. This book is intended to make a contribution to the UNCOVER initiative, which has identified improved information on the subsurface as a prerequisite for extending exploration in Australia from regions of exposure into those with sedimentary cover. To aid in cross comparison of results from different disciplines an effort has been made to present all continental scale geophysical information with a common format and map projection. It is hoped that this compilation of the many different facets of geophysical studies of the continent will make a contribution to the understanding of Australia's lithospheric architecture and its evolution. We have not attempted to impose interpretations on the datasets, rather we believe that the diverse strands of information may inspire new ways of looking at the continent.

The Upper Burdekin Basalt extents web service delivers province extents, detailed geology, spring locations and inferred regional groundwater contours for the formations of the Nulla and McBride Basalts. This work has been carried out as part of Geoscience Australia's Exploring for the Future program.

Abstract submitted for presentation to European Geosciences Union General Assembly, April, 2019

To deliver open data, government agencies must deal with legacy processes, both social and technical, that contain barriers to openness. These barriers limit the true usability of open data - how it can be used over time and in multiple contexts - and are critical to address as governments seek to expose open data. Linked Data (LD) has always been, at its core, about ensuring the FAIR Data Principles (Findable, Accessible, Interoperable, Reusable) by focusing on the identity and relationship of entities and exposing their context to consumers of data, even if these principles have only recently been named FAIR. A fundamental component of LD is that entities are identified by sustainable URI references called Persistent Identifiers (PIDs) which retain their utility over time despite system and organisation change. This poster will show how Geoscience Australia (GA) is applying the use of LD & PIDS in a real world, production IT, setting. Long running operational processes have been incrementally advanced to deliver data from relational databases as LD. Policies, practices and tools have developed and applied to support these LD delivery. The key components are: Data transformation tools: reliant on a robust internal data schema, the Corporate Data Model, these tools export views of it as XML or CSV publicly which is then converted to RDF in another step Overarching data model: a Semantic Web ontology that outlines the types of entities delivered publicly by GA and their macro relations. To date, public entities are Datasets, Web Services, vocabulary terms and geological Samples, Sites Surveys and Stratigraphic Units. New objects will include images with multiple formats and resolutions PID service: an application that manages a series of PID redirection rules PID governance policy: the defined process to support the agency with its multiple teams and their different data sources to have consistent application of entity identification rules and ensure uniqueness across multiple systems in the same registers pyLDAPI data service tools: a Web API tool that can present LD endpoints for entities according to given ontologies Cloud infrastructure as code (infracode): Provisioning of LD data holding RDF triple stores on the public cloud following agency best practice in delivering scalable solutions. The tools used are Apache’s Jena/Fuseki triplestore and API deployed on Amazon Web Services (AWS) with scalability through AWS Elastic Load Balancer and Elastic File Store components. Further work will explore suitability of the new triple store on AWS Neptune.