From 1 - 10 / 476
  • This web service delivers metadata for onshore active and passive seismic surveys conducted across the Australian continent by Geoscience Australia and its collaborative partners. For active seismic this metadata includes survey header data, line location and positional information, and the energy source type and parameters used to acquire the seismic line data. For passive seismic this metadata includes information about station name and location, start and end dates, operators and instruments. The metadata are maintained in Geoscience Australia's onshore active seismic and passive seismic database, which is being added to as new surveys are undertaken. Links to datasets, reports and other publications for the seismic surveys are provided in the metadata.

  • Publicly available data was compiled to provide a common information base for resource development, environmental and regulatory decisions in the north Bowen Basin. This web service summarises oil and gas prospectivity of the north Bowen Basin.

  • In Australia there is a lack of retrospective building regulation to address earthquake prone buildings within communities. The commitment of funds to retrofit high risk buildings either by property owners for by government requires decisions to commit constrained resources for this purpose. Engineers are able to communicate the physical solutions to address these buildings but may be less able to articulate the risk reduction proposition to property owners who may reside or operate a business in the building. Further, emergency managers and government policy makers may not understand the broader issues and benefits of targeted intervention. This paper focusses on unreinforced masonry and describes a program of work that has translated earthquake hazard and engineering vulnerability into a range of communication products. Learnings from the application of masonry mitigation research in two case study communities are presented along with their translation into a range of communication products tailored to a range of decision makers and users. The range of benefits considered are broader than damage avoidance, extending to emergency management logistics, economic activity and avoiding losing heritage value in communities. It also describes forward initiatives to integrate earthquake retrofit into broader resilience building interventions that address other natural hazard deficiencies. Abstract submitted to/presented at the 2022 Australian Earthquake Engineering Society (AEES) Conference (https://aees.org.au/aees-conference-2022/).

  • Geoscience Australia is Australia’s pre-eminent public sector geoscience organisation and is the Australian Government's trusted advisor on the geology and geography of Australia. Geoscience Australia is partnering with the Department of the Environment and Energy’s Geological and Bioregional Assessment (GBA) Program to provide information that will assess the environmental impacts of shale and tight gas development to inform regulatory frameworks and appropriate management approaches. Through this program, Geoscience Australia are conducting passive seismic monitoring deployments in the Beetaloo Sub-basin region of Northern Territory. This monitoring project aims to gather new information about natural seismic (i.e., earthquake) activity and to monitor any change to the environment due to planned hydraulic fracturing activities in the region. This information will be used by Geoscience Australia, the public and other organisations to build knowledge of potential human-induced seismic activity that may affect communities or the environment.

  • Geoscience Australia has produced a draft National Seismic Hazard Assessment (NSHA18), together with contributions from the wider Australian seismology community. This paper provides an overview of the provisional peak ground acceleration (PGA) hazard values and discusses rationale for changes in the proposed design values at the 1/500-year annual exceedance probability (AEP) level relative to Standards Australia’s AS1170.4–2007 design maps. The NSHA18 update yields many important advances on its predecessors, including: consistent expression of earthquake magnitudes in moment magnitude; inclusion of epistemic uncertainty through the use of third-party source models; inclusion of a national fault-source model; inclusion of epistemic uncertainty on fault-slip-model magnitude-frequency distributions and earthquake clustering; and the use of modern ground-motion models through a weighted logic tree framework. In general, the 1/500-year AEP seismic hazard values across Australia have decreased relative to the earthquake hazard factors the AS1170.4–2007, in most localities significantly. The key reasons for the decrease in seismic hazard factors are due to: the reduction in the rates of moderate-to-large earthquakes through revision of earthquake magnitudes; the increase in b-values through the conversion of local magnitudes to moment magnitudes, particularly in eastern Australia, and; the use of modern ground-motion attenuation models. Whilst the seismic hazard is generally lower than in the present standard, we observe that the relative proportion of the Australian landmass exceeding given PGA thresholds is consistent with other national hazard models for stable continental regions. Abstract presented at the 2017 Australian Earthquake Engineering Society (AEES) Conference

  • Damaging earthquakes in Australia and other regions characterised by low seismicity are considered low probability, high consequence events. Uncertainties in modeling earthquake occurrence rates and ground motions pose unique challenges to forecasting seismic hazard in these regions. In 2018 Geoscience Australia released its National Seismic Hazard Assessment (NSHA18). Results from the NSHA18 indicate significantly lower seismic hazard across almost all Australian localities at the 1/500 annual exceedance probability (AEP) relative to the factors in the Australian earthquake loading standard; the AS1170.4. Due to concerns that the 1/500 AEP hazard factors proposed in the NSHA18 would not assure life safety throughout the continent, the amended AS1170.4 (revised in 2018) retains seismic demands developed in the early 1990s and also introduces a minimum hazard design factor of Z = 0.08 g. The hazard estimates from the NSHA18 have challenged notions of seismic hazard in Australia in terms of the probability of damaging ground motions and raises questions as to whether current practices in probabilistic seismic hazard analysis (PSHA) deliver the outcomes required to protect communities in low-seismicity regions, such as Australia. By contrast, it is also important that the right questions are being asked of hazard modelers in terms of the provision of seismic demand objectives that are fit for purpose. In the United States and Canada, a 1/2475 AEP is used for national hazard maps due to concerns that communities in low-to-moderate seismicity regions are considerably more at risk to extreme ground-motions. The adoption of a 1/2475 AEP seismic demands within the AS1170.4 would bring it in to line with other international building codes in similar tectonic environments and would increase seismic demand factors to levels similar to the 1991 hazard map. This, together with other updates, may be considered for future revisions to the standard. Presented at the Technical Sessions of the 2021 Seismological Society of America Annual Meeting (SSA)

  • There has been a long-identified need in New Zealand for a community-developed three-dimensional model of active faults that is accessible and available to all. Over the past year, work has progressed on building and parameterising such a model – the New Zealand Community Fault Model (NZ CFM). The NZ CFM will serve as a unified and foundational resource for many societally important applications such as the National Seismic Hazard Model, Resilience to Natures Challenges Earthquake and Tsunami programme, physics-based fault systems modelling, earthquake ground-motion simulations, and tsunami hazard evaluation. Version 1.0 of the NZ CFM is nearing finalisation and release. NZ CFM v1.0 provides a simplified 3D representation of New Zealand’s crustal-scale active faults (including some selected potentially active faults) compiled at a nominal scale of 1:500,000 to 1:1,000,000. NZ CFM faults are defined based on surface traces, seismicity, seismic reflection profiles, wells, and geologic cross sections. The model presently incorporates more than 800 objects (i.e., faults), which include triangulated surface representations of those faults and associated parameters such as dip and dip direction, seismogenic rupture depth, sense of movement, slip direction, and net slip rate. Presented at the 2021 New Zealand Society for Earthquake Engineering (NZSEE) Conference (https://www.nzsee.org.nz/event/2021-nzsee-conference/)

  • This repository contains a static version of the data and software that accompanies the article by Stephenson et al. (2024) published in the Journal of Geophysical Research: Solid Earth. Note that the data and software repositories are up to date as of 07/03/2024. For more recent updates users are referred to the primary repositories on Github. Contents of zipped repository files includes four directories: 1. The manuscript directory `STEPHENSON_ET_AL_2024_JGR/` containing - The manuscript file (pre-print before final peer review and acceptance by the journal). - Supplementary text accompanying the manuscript. 2. The `SMV2rho` software package version `v1.0.1` for converting seismic velocity into density. 3. The `SeisCruST` database of global crustal thickness and velocity profiles. 4. The `global-residual-topography` database containing estimates of continental residual topography after correcting for isostatic effects of crustal thickness and density variations. Abstract for the article: Continental topography is dominantly controlled by a combination of crustal thickness and density variations. Nevertheless, it is clear that some additional topographic component is supported by the buoyancy structure of the underlying lithospheric and convecting mantle. Isolating these secondary sources is not straightforward, but provides valuable information about mantle dynamics. Here, we estimate and correct for the component of topographic elevation that is crustally supported to obtain residual topographic anomalies for the major continents, excluding Antarctica. Crustal thickness variations are identified by assembling a global inventory of 26 725 continental crustal thickness estimates from local seismological datasets (e.g. wide-angle/refraction surveys, calibrated reflection profiles, receiver functions). In order to convert crustal seismic velocity into density, we develop a parametrization that is based upon a database of 1 136 laboratory measurements of seismic velocity as a function of density and pressure. In this way, 4 120 new measurements of continental residual topography are obtained. Observed residual topography mostly varies between±1–2 km on wavelengths of 1 000–5 000 km. Our results are generally consistent with the pattern of residual depth anomalies observed throughout the oceanic realm, with long-wavelength free-air gravity anomalies, and with the distribution of upper mantle seismic velocity anomalies. They are also corroborated by spot measurements of emergent marine strata and by the global distribution of intraplate magmatism that is younger than 10 Ma. We infer that a significant component of residual topography is generated and maintained by a combination of lithospheric thickness variation and sub-plate mantle convection. Lithospheric composition could play an important secondary role, especially within cratonic regions.

  • Geoscience Australia’s Exploring for the Future program provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia’s geology and resource potential. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia’s transition to net zero emissions, strong, sustainable resources and agriculture sectors, and economic opportunities and social benefits for Australia’s regional and remote communities. The Exploring for the Future program, which commenced in 2016, is an eight year, $225m investment by the Australian Government. The name ‘Birrindudu Basin’ was first introduced by Blake et al. (1975) and Sweet (1977) for a succession of clastic sedimentary rocks and carbonates, originally considered to be Paleoproterozoic to Neoproterozoic in age, and overlain by the Neoproterozoic Victoria Basin (Dunster et al., 2000), formerly known as the Victoria River Basin (see Sweet, 1977).

  • Geoscience Australia has permanently deployed 40 trihedral corner reflectors in Queensland, Australia, covering an area of approximately 20,000 km2. The array of corner reflectors was constructed as part of the AuScope Australian Geophysical Observing System (AGOS) initiative to monitor crustal deformation using Interferometric Synthetic Aperture Radar (InSAR) techniques. The array includes 34 corner reflectors of 1.5m, 3 reflectors of 2.0m and 3 reflectors of 2.5m inner leg dimensions. Through the design process and the precision manufacturing techniques employed, the corner reflectors are also highly suitable for calibration and validation of satellite-borne Synthetic Aperture Radar (SAR) instruments. Nine of the 1.5m corner reflectors in the AGOS array had their Radar Cross Section (RCS) individually characterised at the Defence Science and Technology Organisation¿s outdoor ground reflection range, prior to permanent deployment in Queensland. The RCS measurements for the corner reflectors were carried out at X and C-band frequencies for both horizontal and vertical transmit-receive polarisations, and at a range of elevation and azimuth alignments. The field performance of the AGOS corner reflectors has been studied using SAR data from a range of satellites including Sentinel-1A. This study focuses on the calibration of the Sentinel-1A satellite presenting results from exercises undertaken both at Geoscience Australia and the European Space Agency¿s Mission Performance Centre as part of the satellite commissioning and routine phases. Radiometric calibration results in conjunction with geometric calibration and validation results for Sentinel-1A products from Stripmap and Terrain Observation with Progressive Scans (TOPS) modes are presented in this paper. The current configuration for most corner reflectors in the AGOS array is set to serve calibration requirements for a broad range of SAR missions on ascending orbital passes. However, the design allows for mission-specific corner reflector alignment if needed, as in the case of the 2.5m and 2.0m reflectors which have specifically been aligned to support calibration of the L-band SAR instrument on ALOS-2. Results reported in this paper could inform the need for re-configuring one or more corner reflectors in the array to specifically support ongoing calibration of the Sentinel-1A and B satellites. The permanently deployed AGOS corner reflector infrastructure presents an opportunity for independent calibration and comparison of SAR instruments on current and future satellite missions, and is considered an important Australian contribution to the global satellite calibration and validation effort. Presented at the 2016 Living Planet Symposium (LPS16) Prague, Czech Republic