CWAS: A Dense Passive-Source Seismic Survey to Image Northwestern Australia

Abstract

Northwestern Australia preserves a complex record of Precambrian craton formation and passive-margin evolution, yet its lithospheric structure remains poorly constrained because of thick sedimentary cover and sparse seismic observations. To address this gap, the China–Western Australia Seismic Survey was conducted between 2017 and 2019 by the Institute of Geology and Geophysics, the Chinese Academy of Sciences, Macquarie University, and the Geological Survey of Western Australia. The survey deployed 56 broadband land stations along a ∼900 km transect, complemented by 8 ocean-bottom seismometers on a ∼500 km offshore line—the first integrated land–ocean passive-source seismic array in this region. Most of land stations recorded continuously for more than one year. All waveforms and metadata are openly available through the Australian Passive Seismic Server (International Federation of Digital Seismograph Networks network code 4N). Example data products, including receiver functions, ambient-noise cross correlations, and earthquake waveforms demonstrate the dataset’s suitability for crustal and lithospheric imaging. The offshore component, documented here for the first time, extends seismic coverage across the ocean–continent transition and provides a new resource for future studies of passive-margin structure and evolution.