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.

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

This animation shows how passive seismic surveys Work. It is part of a series of Field Activity Technique Engagement Animations. The target audience are the communities that are impacted by our data acquisition activities. There is no sound or voice over. The 2D animation includes a simplified view of what passive seismic equipment looks like, what the equipment measures and how the survey works.

For more than half a century, seismic tomography has been used to map the volumetric structure of Earth’s interior, but only recent advances in computation have enabled the application of this technique at scale. Estimates of surface waves that travel between two seismic stations can be reconstructed from a stack of cross-correlations of continuous data recorded by seismometers. Here, we use data from the Exploring for the Future program AusArray deployment to extract this ambient noise signal of Rayleigh waves and use it to image mid- to upper-crustal structure between Tennant Creek and Mount Isa. Our aim was to establish a repeatable, semi-automatic workflow that can be extended to the entire Australian continent and beyond. Shear wave velocity models at 4, 6, 8 and 10 s periods are presented. A strong low-velocity anomaly (2.5 km/s) at a period of 4 s (~2–4 km depth) delineates the outline of the newly discovered, and prospective for hydrocarbons, Carrara Sub-basin. A near-vertical high-velocity anomaly (3.5 km/s) north of Mount Isa extends from the near surface down to ~12 km and merges with northeast-trending anomalies. These elongate features are likely to reflect compositional variations within the mid-crust associated with major structures inferred to be associated with base metal deposits. These outcomes demonstrate the utility of the ambient noise tomography method of imaging first-order features, which feed into resource potential assessments. <b>Citation: </b>Hejrani, B., Hassan, R., Gorbatov, A., Sambridge, M. Hawkins, R., Valentine, A., Czarnota, K. and Zhao, J., 2020. Ambient noise tomography of Australia: application to AusArray deployment. 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. <b>See eCat record <a href="https://dx.doi.org/10.26186/148676">#148676</a> for the updated version of the model package.</b>

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>

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.

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 Exploring for the Future program Showcase 2024 was held on 13-16 August 2024. Day 2 - 14th August talks included: <b>Session 1 - Architecture of the Australian Tectonic Plate</b> <a href="https://youtu.be/a8jzTdNdwfk?si=OWNlVR-FLDhF1GVM">AusArray: Australian lithosphere imaging from top to bottom</a> - Dr Alexei Gorbatov <a href="https://youtu.be/j5ox8Ke5n6M?si=YkfDno2xmZXueS1b">AusLAMP: Mapping lithospheric architecture and reducing exploration space in Australia</a> - Jingming Duan <a href="https://youtu.be/qZ6wjzx_dNc?si=NjDEzvqyEeM24-E8">Constraining the thermomechanical and geochemical architecture of the Australian mantle: Using combined analyses of xenolith inventories and seismic tomography</a> - Dr Mark Hoggard <b>Session 2 - Quantitative characterisation of Australia's surface and near surface</b> <a href="https://youtu.be/nPfa_j3_dos?si=mktfIJWXeLElIOK4">AusAEM: The national coverage and sharpening near surface imaging</a> - Dr Anandaroop Ray <a href="https://youtu.be/SU6ak98JvAw?si=DQPovulHa4poqcm0">Unlocking the surface geochemistry of Australia</a> - Phil Main <a href="https://youtu.be/Xtm45CT6e-s?si=JHU7J-ktgVrbj1Ke">Spotlight on the Heavy Mineral Map of Australia</a> - Dr Alex Walker <b>Session 3 – Maps of Australian geology like never before</b> <a href="https://youtu.be/aRISb1YYigU?si=3byJbqW0qRTqCB8-">An Isotopic Atlas of Australia: Extra dimensions to national maps</a> - Dr Geoff Fraser <a href="https://youtu.be/khSy-WAkw-w?si=F-Y67FX3jXN5zZaz">First continental layered geological map of Australia</a> - Dr Guillaume Sanchez <a href="https://youtu.be/Z3GlCJepLK4?si=k_tbaKdmxGBmoSro">An integrated 3D layered cover modelling approach: Towards open-source data and methodologies for national-scale cover modelling</a> - Sebastian Wong View or download the <a href="https://dx.doi.org/10.26186/149800">Exploring for the Future - An overview of Australia’s transformational geoscience program</a> publication. View or download the <a href="https://dx.doi.org/10.26186/149743">Exploring for the Future - Australia's transformational geoscience program</a> publication. You can access full session and Q&A recordings from YouTube here: 2024 Showcase Day 2 - Session 1 - <a href="https://www.youtube.com/watch?v=EHBsq0-pC8c">Architecture of the Australian Tectonic Plate</a> 2024 Showcase Day 2 - Session 2 - <a href="https://youtube.com/watch?v=xih4lbDk-1A">Quantitative characterisation of Australia's surface and near surface</a> 2024 Showcase Day 2 - Session 3 - <a href="https://www.youtube.com/watch?v=qeTLc1K-Cds">Maps of Australian geology like never before</a>

<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>

<div>This model is a volumetric representation of receiver function analysis based on common conversion point (CCP) profiles created every 50 km in North-South and East-West directions below the AusArray network (Gorbatov et al., 2020), combining them into one 3D image. The model bounds are: (-21.74, 132.52) - (-17.30, 141.46), geographic projection EPSG:28353. The model file is distributed in ASCII GoCad stratigraphic grid format (SGrid) where units are longitude (meters), latitude (meters), depth (meters) and value of receiver function amplitude.</div><div><br></div><div>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 a low emissions economy, strong 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.</div>