Characteristics of the Oceanic Ambient Seismic Noise Around Tristan da Cunha in the South Atlantic From OBS Data
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Published:2023-05-27
Issue:6
Volume:128
Page:
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ISSN:2169-9313
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Container-title:Journal of Geophysical Research: Solid Earth
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language:en
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Short-container-title:JGR Solid Earth
Author:
Zhang Hao123ORCID,
Schmidt‐Aursch Mechita C.3ORCID,
Geissler Wolfram H.3ORCID,
Xing Junhui1ORCID
Affiliation:
1. College of Marine Geosciences Ocean University of China Qingdao China
2. Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology Qingdao China
3. Helmholtz Centre for Polar and Marine Research Alfred Wegener Institute Bremerhaven 27570 Germany
Abstract
AbstractIt has long been recognized that specific ambient seismic noise is generated within the ocean. Therefore, ocean bottom seismometers have advantages to reveal the noise characteristics directly in the deep sea. We use the seismic recordings around Tristan da Cunha collected by 20 OBSs and two island stations to investigate the ambient noise sources in the middle of the South Atlantic. We analyzed the power spectral density, ambient noise cross‐correlations, and correlations with wave heights model. While primary microseisms (∼10–20 s) in this region are deficient, the secondary microseisms are strong and dominate the ambient noise at periods of ∼1–10 s, with the peak broadening to shorter periods (1–3 s). The secondary microseisms are strongly correlated with the local wave heights, especially at shorter periods (∼1–3 s), suggesting that the microseisms are affected mostly by local wave interactions. We observed clear Empirical Green's functions at periods of ∼3–10 s, indicating the existence of distant sources of secondary microseisms. Results of asymmetry analysis of cross‐correlations suggest the prominent direction of the distant source should be located to the Southwest and show barely seasonal variations. The correlations with wave heights indicate a possible source region in the southeast Pacific Ocean. Therefore, besides the dominating local wave‐wave interactions, the secondary microseisms around Tristan region are affected simultaneously by persistent distant sources from the deep basin in the Southeast Pacific Ocean, which might be related to the intense wave‐wave interactions caused by the blocking effect of the Drake Passage on ocean currents and waves.
Funder
China Scholarship Council
National Key Research and Development Program of China
National Natural Science Foundation of China
Fundamental Research Funds for the Central Universities
Deutsche Forschungsgemeinschaft
Publisher
American Geophysical Union (AGU)
Subject
Space and Planetary Science,Earth and Planetary Sciences (miscellaneous),Geochemistry and Petrology,Geophysics
Cited by
1 articles.
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