Abstract We present a new machine-learning-based catalog of southwestern Australia, a stable intraplate zone primarily comprised of the Archean aged Yilgarn craton and the continent’s most seismically active region. About 29,000 events were located between 2000 and May 2025 with 43% of these presumed to be related to anthropogenic mining based on location and temporal filtering. Most (75%) events were located following the new SWAN (2P, 2020) and WA Array networks (WG, 2022), which collectively added ∼340 stations from 2020 to 2025 and were the first to target this region in detail. We observe a very high degree of spatially correlated clustering, which contains power-law, Omori-type mainshock–aftershock behavior as well as low-volume and low-magnitude atemporal clustering we label as “drip-type” behavior. Drip-type clustering is presumed to reflect the long-tail baseline activity following the cessation of temporally correlated behavior following large earthquakes, but may also be unrelated to past activity. As such, the identification of drip-type clusters could be used to infer the location of prehistoric seismicity and future seismic risk. Three recent significant earthquake sequences were also analyzed in detail: Arthur River (2022), Gnowangerup (2023), and Wyalkatchem (2024), which is still producing significant seismicity as of publication. In each, the distribution of hypocenters is shallow (5 km) but mostly disorganized, no clear fault plane could be resolved, and the largest event in the sequence was preceded by a significant but smaller magnitude earthquake by several weeks to months. All three sequences also show centroid moment tensor solutions consistent with the expected west–east compression regime in southwest Australia. “Drip-type” activity preceded both Gnowangerup and Wyalkatchem, but the earthquakes at Arthur River sequence were the first at that location in our catalog.
Pickle et al. (Thu,) studied this question.