<div>The active seismic and passive seismic database contains metadata about Australian land seismic surveys acquired by Geoscience Australia and its collaborative partners. </div><div>For active seismic this is onshore surveys with metadata including 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. Each also contains a field that contains links to the published data. </div><div><br></div><div>The active and passive seismic database is a subset of tables within the larger Geophysical Surveys and Datasets Database and development of these databases was completed as part of the second phase of the Exploring for the Future (EFTF) program (2020-2024). The resource is accessible via the Geoscience Australia Portal&nbsp;(https://portal.ga.gov.au/), under 'Geophysics'. Use 'active seismic' or 'passive seismic' as search terms. </div><div><br></div>

To improve exploration success undercover, the UNCOVER initiative identified high-resolution 3D seismic velocity characterisation of the Australian plate as a high priority. To achieve this goal, the Australian Government and academia have united around the Australian Passive Seismic Array Project (AusArray). The aim is to obtain a national half-degree data coverage and an updatable 3D national velocity model, which grows in resolution as more data become available. AusArray combines data collected from the Australian National Seismological Network (ANSN), multiple academic transportable arrays (supported by AuScope and individual grants) and the Seismometers in Schools program. The Exploring for the Future program has enable the unification of these datasets and a doubling of the national rate of data acquisition. Extensive quality control checks have been applied across the AusArray dataset to improve the robustness of subsequent tomographic inversion and interpretation. These data and inversion code framework allow robust national-scale imaging of the Earth to be rapidly undertaken at depths of a few metres to hundreds of kilometres. <b>Citation:</b> Gorbatov, A., Czarnota, K., Hejrani, B., Haynes, M., Hassan, R., Medlin, A., Zhao, J., Zhang, F., Salmon, M., Tkalčić, H., Yuan, H., Dentith, M., Rawlinson, N., Reading, A.M., Kennett, B.L.N., Bugden, C. and Costelloe, M., 2020. AusArray: quality passive seismic data to underpin updatable national velocity models of the lithosphere. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4. http://dx.doi.org/10.11636/135284 <b>Data for this product are available on request from clientservices@ga.gov.au (see data description). Last updated 08/08/2024 - Quote eCat# 135284</b>

<div>As part of the first phase (2016-2020) of the Exploring for the Future (EFTF) program, Geoscience Australia deployed 119 broad band seismic stations in northern Australia. This deployment was part of the Australian Passive Seismic Array (AusArray) Project. Data from these stations were used to image the seismic structure using various techniques, including ambient noise tomography (ANT). The first ANT model (Hejrani et al, 2020) was focused on a narrow range of frequencies and used the Hawkins and Sambridge (2019) approach to estimate dispersion curves. This new approach starts from the original work by Aki (1957) to estimate phase velocity in the frequency domain, and then takes a step further to ensure a smooth curve is achieved. In Hejrani et al., (2022), using minimum Signal-to-Noise-Ratio (SNR) threshold of 2, about 4,000 data points (out of 7,000+) were used to generate surface wave velocity maps at a resolution of 1 degree at four frequencies (sensitive to different depths). This model was subsequently updated in September 2021 by using all 7,000+ data points (no SNR threshold) of phase velocity measurements across AusArray year one to provide a 0.25 degree resolution model. All dispersion curves regardless of their quality were utilized. A number of artefacts were identified in that model, which motivated further investigations. During 2022, I developed a new automated and scalable approach to estimate dispersion curves, which was completed in December 2022. This new method starts from the original idea by Aki (1957), but takes a different approach to stabilize the dispersion curves and to avoid cycle skipping. </div><div>This record represents the preferred 2D velocity models for AusArray year one data based on the newly estimated dispersion curves and a comparison with previous models and interpretations; is an update from Hejrani et al. (2020) and should be read in conjunction. Work is currently under way to invert these 2D surface wave models to obtain 3D velocity models for the crust and mantle. Such 3D velocity models would be suitable for joint interpretations with other data such active seismic, gravity and magnetic. The code will be made publicly available at the conclusion of EFTF.</div>

Exploration and management of minerals, energy and groundwater resources requires robust constraints on subsurface geology. Over the last decade the passive seismic technique has grown in popularity as it is one of a handful of non-invasive methods of imaging the subsurface. Given regional imaging relies on comparing records of ground motion between simultaneous deployments of seismometers deployed for over a year, consistency and quality of data collection lies at the heart of this technique. Here, we summarise the standard operating procedures developed by Geoscience Australia over the last 6 years for deployment, servicing and retrieval of passive seismic arrays. Our purpose is to share our experience and thereby contribute to improving the quality of passive seismic data being acquired across Australia. <b>Citation:</b> Holzschuh J., Gorbatov A., Glowacki J., Cooper A. & Cooper C., 2022. AusArray temporary passive seismic station deployment, servicing and retrieval: Geoscience Australia standard operating procedures. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/146999

Geoscience Australia, in collaboration with state government agencies, has been collecting magnetotelluric (MT) data as part of the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) for several years. This program aims to map the electrical resistivity of the rock layers, at depths from ten kilometres to hundreds of kilometres, across the entire continent. AusLAMP sites are each about 55 km apart from each other. Locations are chosen in consultation with landholders and other stakeholders to minimise impacts and avoid disturbance.MT data is collected using sensors that record naturally occurring variations of the Earth’s magnetic and electric fields. The equipment does not produce or transmit and signals. After four to six weeks the equipment is retrieved and the site restored to its original condition.

<div><strong>Output type: </strong>Exploring for the Future Extended Abstract</div><div><br></div><div><strong>Short abstract: </strong>Passive seismic methods serve as versatile tools for probing Earth structure and facilitating new geological and geodynamic insight across vast areas. Tomographic velocity models derived from continental scale passive seismic data are becoming increasingly important in guiding resource exploration into prospective regions. While Australia has been leading this field our existing data coverage and quality is insufficient resulting in large uncertainties in continental scale models. With the aim of robustly constraining Australia’s lithospheric architecture the Exploring for the Future (EFTF) program began collection of a 2° (~220 km spaced) AusArray passive seismic data coverage. There are over 150 broad-band seismometer stations simultaneously deployed across Australia for a period of up to two years - a pioneering effort on a continental scale. The quality assurance/quality control (QA/QC) analysis and deployment approaches, refined during previous 0.5° (~55 km spaced) campaigns, were rigorously applied to prevent data errors or data loss. Advanced standard operating procedures and stakeholder engagement materials were developed and openly shared with broader professional communities to support similar activities, fostering the continued advancement of passive seismic methods in both industry and research. The resulting data will be shared via the eCat system in raw format, accompanied by a StationXML file that holds the QA/QC information. This file can be used to apply QA/QC results to raw waveforms, enabling their use in subsequent analysis and modelling endeavors. Insights from this survey will guide future higher resolution AusArray deployments. &nbsp;</div><div><br></div><div><strong>Citation: </strong>Gorbatov, A., Hejrani, B., Holzschuh, J., Zhao, J., Hassan, R., Cathro, D., Czarnota, K., Kuoni, J., Sweeney, M., Glowacki, J., Murdie, R., O'Donnel, J.P. & Haydon, S.J., 2024. AusArray continent-scale deployment. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://doi.org/10.26186/149640 </div>

The AusArray program aims to install small temporary passive seismic stations every 200 km across Australia. The seismic stations will passively measure small natural vibrations that travel through the Earth to help scientists understand the distribution and composition of rocks beneath the ground. Seismometers are sensitive instruments used to measure small natural vibrations that travel through the Earth caused by earthquakes, waves breaking on the shore and even wind. The data collected are analysed to create a three-dimensional model of the Earth’s subsurface. Passive seismic data can be used to model the Earth‘s structure, which is used to infer the geological history and assess the resource potential and natural hazards of the region.

Geoscience Australia’s Exploring for the Future program (EFTF) provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. The Australian Passive Seismic Array Project (AusArray) program developed from a long history of passive seismic imaging in Australia involving many contributors. Building on this history, the Australian Government (EFTF), academia and state governments have united around AusArray. The objective is a standardised and quality controlled national passive seismic data coverage and an updatable national seismic velocity model framework that can be used as a background for higher-resolution studies. The AusArray passive seismic data are supplemented with active seismic data that can provide P-wave and S-wave velocity information for the near surface down to about 50 m depth. This near-surface velocity data will provide constraints for some AusArray passive seismic data modelling to obtain more reliable depth models. This document details the active seismic data acquisition using TROMINO® three-axis broadband seismometers using a wireless trigger and hammer source. Equipment packing, field operations, data extraction and preparation, and Multichannel Analysis of Surface Waves (MASW) modelling are described.

The Australian Passive Seismic Array Project (AusArray) program was developed from a long history of passive seismic imaging in Australia involving many contributors. Building on this history, the Australian Government and academia have united around AusArray. The objective is a standardised and quality controlled national passive seismic data coverage and an updatable national seismic velocity model framework that can be used as a background for higher-resolution studies. This document details the field activities and equipment preparation for temporary passive seismic station deployment, service and retrieval. Equipment cleaning and testing and database details are also described. The standard operating procedures applied during these activities were established during the deployment of two temporary passive seismograph arrays under the Australian Government’s Exploring for the Future (EFTF) program. These arrays consisted of 120–130 stations deployed in the Northern Territory and Queensland for over a year in a grid pattern with a lateral spacing of half a degree (~55 km). The temporary passive seismograph stations comprised Nanometrics Trillium Compact 120S broadband seismic sensors connected to a Güralp minimus digitiser. Batteries charged by a solar panel powered both instruments. Each station in the array was serviced, i.e. repairs if required and interim data was retrieved, at least once during the deployment.

This is a collection of continuous seismic records gathered by temporal and semi-permanent seismic deployments where real-time data transmission was not available. Time spans vary from half an hour to more than a year depending on the purpose of the survey. Description of the employed instrumentation and array constellations can be found in the accompanied material. <b>Value: </b>Passive seismic data contains records of soil vibration due to the natural earth movements, ocean, weather, and anthropogenic activities. This data is used in ongoing research to infer national lithospheric structure from depth of a few meters to a hundred kilometres. Derived models are an important source of information for assessment of resource potential and natural hazard. <b>Scope: </b>Over time, surveys have been focused on areas of economic interest, current work of the Australian Passive Seismic Array Project (AusArray) is seeking to create a grid pattern, spaced ~55 km apart, and complemented by semi-permanent higher sensitivity broadband seismic stations. For more information about AusArray click on the following URL: <a href="https://www.ga.gov.au/eftf/minerals/nawa/ausarray">https://www.ga.gov.au/eftf/minerals/nawa/ausarray</a> <b>Data from phase 1 are available on request from clientservices@ga.gov.au - Quote eCat# 135284</b>