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Published June 1, 2023 | public
Journal Article

Seismic noise characterisation at a potential gravitational wave detector site in Australia

Abstract

A critical consideration in the design of next-generation gravitational wave detectors is the understanding of the seismic environment that can introduce coherent and incoherent noise of seismic origin at different frequencies. We present detailed low-frequency ambient seismic noise characterisation (0.1–10 Hz) at the Gingin site in Western Australia. Unlike the microseism band (0.06–1 Hz) for which the power shows strong correlations with nearby buoy measurements in the Indian Ocean, the seismic spectrum above 1 Hz is a complex superposition of wind induced seismic noise and anthropogenic seismic noise which can be characterised using beamforming to distinguish between the effects of coherent and incoherent wind induced seismic noise combined with temporal variations in the spatio-spectral properties of seismic noise. This also helps characterise the anthropogenic seismic noise. We show that wind induced seismic noise can either increase or decrease the coherency of background seismic noise for wind speeds above 6 m s−1 due to the interaction of wind with various surface objects. In comparison to the seismic noise at the Virgo site, the secondary microseism (0.2 Hz) noise level is higher in Gingin, but the seismic noise level between 1 and 10 Hz is lower due to the sparse population and absence of nearby road traffic.

Additional Information

© 2023 IOP Publishing. This project was supported by the Australian Research Council (ARC) Centre of Excellence for Gravitational Wave Discovery (CE170100004), ARC LIEF Grant (LE200100008) and CSIRO Deep Earth Imaging Future Science Platform. The authors would like to also thank Siobain Mulligan and the Oceanographic Services at the Department of Transport of Western Australia for providing the Indian Ocean wave data (buoy measurements) used in this study. Finally, we appreciate Dr Soumen Koley at Gran Sasso Science Institute in Italy for providing us with the seismic data of the Virgo site used in this paper. This project was supported by the Australian Research Council (ARC) Centre of Excellence for Gravitational Wave Discovery (CE170100004), ARC LIEF Grant (LE200100008) and CSIRO Deep Earth Imaging Future Science Platform. The authors would like to also thank Siobain Mulligan and the Oceanographic Services at the Department of Transport of Western Australia for providing the Indian Ocean wave data (buoy measurements) used in this study. Finally, we appreciate Dr Soumen Koley at Gran Sasso Science Institute in Italy for providing us with the seismic data of the Virgo site used in this paper. Data availability statement. The data cannot be made publicly available upon publication because they are owned by a third party and the terms of use prevent public distribution. The data that support the findings of this study are available upon reasonable request from the authors.

Additional details

Created:
August 22, 2023
Modified:
October 20, 2023