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- Title
Study of S‐Wave Microseisms Generated by Storms in the Southeast Australia and North Atlantic.
- Authors
Xiao, Han; Tanimoto, Toshiro; Xue, Mei
- Abstract
Using continuous data from a dense seismic array in Southwestern China, we tracked S‐wave microseism sources generated by two storms in Southeast Australia and the North Atlantic. In the frequency band 0.1–0.2 Hz, the beam strengths for SV‐ and SH‐wave sources can reach 29% and 18% of P‐wave, respectively. We found that the strong SH‐wave is only observed when the seismic sources are near the thick sedimentary regions whereas P‐ and SV‐wave is irrespective of that. It appears that in addition to a three‐dimensional structure that is needed for conversion from P‐wave to SH‐wave, amplitude enhancement by a sedimentary layer is essential for the detection of SH‐wave. Plain Language Summary: The interactions of ocean waves in the opposite propagation directions generate an equivalent vertical force in the ocean, creating dominant seismic noise in the frequency band 0.1–0.3 Hz. This forcing mechanism can explain the observations of P or Rayleigh waves but cannot explain the observations of SH or Love waves. In this study, from precise locations of SH‐wave sources in Southeast Australia and the North Atlantic, it is shown that SH‐wave sources are only found near a region of the thick sedimentary layer at the sea bottom. Amplification of waves in a thick sedimentary layer seems to be required to excite observable SH‐wave in seismic noise. Key Points: A large, dense seismic array in Southwestern China detects clean S‐wave signals in seismic noiseStrong S‐wave signals were tracked for the storms in Southeast Australia and the North AtlanticThe SH‐wave sources were only observed near thick sediment at the sea bottom, suggesting an amplitude enhancement by sediment is essential
- Subjects
CHINA; AUSTRALIA; SHEAR waves; MICROSEISMS; SEISMIC arrays; RAYLEIGH waves; THEORY of wave motion; OCEAN waves
- Publication
Geophysical Research Letters, 2021, Vol 48, Issue 15, p1
- ISSN
0094-8276
- Publication type
Article
- DOI
10.1029/2021GL093728