Australian Crustal Stress Measurements from Earthquakes and Over-Coring

Evidence from earthquake focal mechanisms and in-situ stress measurements indicates substantial horizontal compression across the Australian continent. Data includes reliable focal mechanism determinations from eight earthquakes since 1967 and in-situ measurements from mines, tunnels, and quarry floors across multiple states. The dataset is provided by the Australian Ocean Data Network and was last updated in April 2026.

Use Cases

• Model regional stress fields by analyzing principal stress orientation (e.g., 77°E of N) and magnitude (e.g., 23 MPa) from over-coring measurements.
• Correlate earthquake focal mechanism pressure axes (e.g., 91° and 102°E of N) with in-situ stress measurements from specific locations like Meckering and Calingiri.
• Map spatial variations in compressive stress direction by comparing north-south axes (e.g., Buckleys Lake) with east-west axes (e.g., Ardlethan) across New South Wales.
• Assess stress magnitude ranges using recorded values from specific sites, such as 4 MPa near the Meckering epicenter and 20 MPa in Silurian granite at Tocumwal.

Strengths

• Includes focal mechanism data from eight continent-spanning earthquakes since 1967.
• Contains in-situ stress measurements from multiple sites along a 200 km north-south traverse.
• Reports specific principal stress magnitudes, with a highest recorded value of 23 MPa.

Limitations

• Sample size for earthquake focal mechanisms is limited to eight events.
• In-situ measurement depths are shallow, typically less than 10 meters.
• Geographic coverage is focused on specific Australian regions and traverses.

Provenance

Source

Australian Ocean Data Network

Collection Method

Combines earthquake focal mechanism analysis with in-situ stress measurements from over-coring in mines, tunnels, and quarry floors.

Time Range

1967 to 1979

Freshness

Data includes measurements from 1967 through 1979, with a platform update in 2026.

Geography

Continent of Australia, with specific sites in Western Australia, New South Wales, and others mentioned.