WA Array is a network of instruments called seismometers that will be set up across Western Australia. Seismometers measure vibrations in the Earth produced by sources such as earthquakes, quarry blasts, the rumblings of trains and vehicles and pounding of ocean waves. Recording these vibrations will teach us more about what the Earth’s crust and deeper layers (called the lithosphere) are made of and how they are structured.
This information will help us identify areas that might have valuable mineral or energy resources deep underground, reduce risks from earthquakes, plan for future land uses and support Western Australia's efforts to move toward net-zero emissions. The project is a big and complex task and is one of the largest and highest resolution of its kind ever done in the world.
WA Array is funded by the Western Australian Government and will run for 10 years. Managed by GSWA, it began in 2022. The project involves placing 165 seismometers in a grid pattern across a region, with each device spaced 40 km apart. These seismometers will be moved yearly to cover nine different regions across the State. Each station needs to be set up, maintained, removed after one year, and the site restored after use. About 52% of the stations will need helicopters for transport, while the rest can be reached by road.
As the seismometers collect data, it will go through strict quality checks before being shared for free with explorers, researchers, and the public through AusPASS: the Australian Passive Seismic Server. Additional maps and 3D models created from the data will be available through our online platforms.
The program will focus first on regions with the highest potential for resource development. The data collected and models produced will be released as each region is completed.
The science behind WA Array
Continents are made up of pieces of lithosphere that have come together over time. The boundaries, or sutures, between these pieces are important for finding new mineral deposits because they connect to deep parts of the Earth and can act as pathways for mineral-rich fluids.
Seismologists use techniques like ‘ambient’ seismic noise—caused by ocean waves and storms—and receiver functions, which measure how earthquake signals change as they travel through the Earth. These methods help create images of the Earth's structure, including the speed and composition of layers beneath the surface.
One key feature is the lithosphere-asthenosphere boundary (LAB), which marks the base of the continental plates. This boundary is crucial for predicting where mineral deposits may be near the surface. High-resolution passive seismic studies can map the LAB and its variations in detail, giving mineral explorers valuable information about where sutures between major lithospheric blocks might be located.
Watch Explaining WA Array to find out more.
You can also learn more by reading our ArcGIS StoryMap, WA Array: listening to the Earth.
The net zero challenge
The world’s shift to a low-carbon economy is driving strong demand for critical minerals needed for renewable energy and storage technologies. To support this, Western Australia needs careful planning to balance land use for renewable energy projects with the exploration and development of new mines and related industries.
Western Australia has one of the most successful and diverse resource sectors globally. It is a top producer of important resources like iron ore, gold, lithium, nickel, and alumina. However, finding new major mineral deposits has become harder, which could affect our ability to meet future demand.
Most known mineral deposits are near the surface or were relatively easy to find. However, about 70% of Western Australia’s prospective basement rocks are hidden under layers of sediment and weathered rock. This makes exploration challenging. Projects like WA Array use advanced geoscience technology to create images of the State’s geology at deep levels, helping exploration companies locate hidden resources more effectively.
Seismic hazards
The South West Seismic Zone is one of the most active earthquake areas in Australia, with regular clusters of earthquakes. This map shows the size (magnitude) and location of earthquakes in Western Australia during 2022. The WA Array project will help pinpoint where new earthquakes occur, giving scientists a clearer understanding of the geological causes of seismic activity and allowing them to create a regional stress map. This information can improve building codes, strengthen infrastructure, and help emergency services focus on high-risk areas.
Big earthquakes can and do happen in Western Australia, causing significant damage. Notable events include the Meckering earthquake in 1968 (magnitude 6.5), Cadoux in 1979 (magnitude 6.1), Kalgoorlie in 2010 (magnitude 5.0), and offshore Broome in 2019 (magnitude 6.6).
WA Array Phase 1
Show moreThe first phase of the WA Array project began with the setup of 128 new passive seismic stations in southwest Western Australia. Another 16 stations from the South West Australia Passive Seismic Network (SWAN) were also serviced and added to the array. The Geological Survey of Western Australia helped install 11 stations from the national AusArray network within the region, which were incorporated into the WA Array. The remaining network was completed with three stations from the Seismometers in Schools program and six stations from the Australian National Seismograph Network, bringing the total to 161 stations for phase one.
The seismic stations use equipment from companies including REF TEK, Nanometrics, Guralp, Silicon Audio, Earth Science Systems and GaiaCode. These include broadband seismometers with 60-second or 120-second capabilities and a variety of digital recorders, such as Reftek Wranglers, Guralp Minimus, ESS Geckos, and Nanometrics Taurus and Centaurs.
Data from all stations was collected after six months, and issues like power problems and timing errors were fixed during site visits. The seismic stations were removed in December 2023 after 1 year in the ground.
See this map for locations of WA Array Phase 1
Waveform data and station metadata can be downloaded through AusPASS: the Australian Passive Seismic Server.
Models and supplementary data can be found in MAGIX Online.
Details on the processing and models from phase 1 will be available in GSWA Report 256 through the DEMIRS eBookshop.
Calibration test
To ensure accuracy, it’s important that all types of seismometers record the same waveform for the same earthquake. To check this, a calibration test was carried out. During the test, all combinations of instruments were set up on the same slab at the same time, and their waveforms were compared. This confirmed that the equipment produced identical traces for the same earthquake.
The calibration test involved running all seismometer–digitiser combinations at the same site to ensure consistent and accurate data across all equipment.
Products and Models
The high-resolution models created from the data include:
- A local seismicity catalogue: A record of earthquakes in the area.
- Vp and Vs crustal models: Showing P-wave and S-wave crustal velocities from local earthquakes.
- Crustal Vs models: Derived using ambient noise tomography.
- VS30 models and depth to basement: Providing near-surface shear wave velocity and information about the depth to the basement rock.
- Moho depths: Determined through receiver function analysis to identify the boundary between the crust and mantle.
- Bulk crustal composition: Understanding the overall makeup of the crust.
- Mantle anisotropy: Insights into the alignment of minerals in the mantle.
- Body wave tomography: Imaging the lithosphere using teleseismic waves.
- Surface wave tomography: Mapping the lithosphere–asthenosphere boundary using surface waves.
WA Array Phase 2
Show moreThe second phase of WA Array began with deployment in February–March 2024. This phase covers an area bordering the east and north of the phase 1 region, stretching from Geraldton to Leonora and Laverton, and down through the Goldfields to Esperance. The first download of data was completed in September 2024 and the removal of the equipment will happen in March 2025
See this map for locations of WA Array Phase 2
WA Array Phase 3
Show moreThe third phase of WA Array is planned for deployment in May 2025. This will be split between the Warburton area of the central east of Western Australia and the Mid-West. The Central East region is very remote, requiring both helicopter access and significant effort from ground crews. As of March 2023, discussions with Traditional Owners are ongoing to ensure the locations are agreed upon by all parties.
See this map for locations of WA Array Phase 3
