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Investigating the Characteristics of Microseisms using the Australian Seismic Arrays
  • Abhay Pandey,
  • Hrvoje Tkalčić,
  • Xiaolong Ma
Abhay Pandey
Research School of Earth Sciences, Australian National University

Corresponding Author:[email protected]

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Hrvoje Tkalčić
Australian National University
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Xiaolong Ma
Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)
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Abstract

Earth’s microseisms are continuously recorded by seismographs worldwide. Yet, studies using broadband digital data to analyze microseisms in Australia have been rare. Building on initial research efforts that relied on the Warramunga array in the continent’s center, we expand the investigation of microseisms by utilizing seismic arrays in various locations and with distinct apertures and geometries, particularly spiral-arm arrays. Motivated by expanding knowledge of microseismic sources, we investigate the distribution and characteristics of microseisms. We process one-year continuous waveform data using beamforming at various periods. Using the back-projection, we then investigate the plausible source areas of surface waves and teleseismic P-waves generated by ocean activity. We also examine the seasonal variability of microseismic sources and their relationship with the ocean wave hindcast model by comparing our observations of Rayleigh (Rg) waves with modelled Rg wave sources and juxtaposing the back-projected P-waves with significant wave heights. Our results suggest that over the time interval of several months and longer, Rayleigh waves are the dominant component arriving from the nearby coastlines. They show a transition to higher mode Lg waves in the higher frequency bands. In contrast, on the time scale of days and weeks, teleseismic P-waves from the coastal and pelagic sources are observed particularly from the tropical and equatorial regions. We also identify new patterns of body waves from the perspective of the Southern Hemisphere. Our study highlights the importance of utilizing multiple arrays and elucidates the critical roles of the frequency range and bathymetry.
24 May 2024Submitted to ESS Open Archive
28 May 2024Published in ESS Open Archive