Characteristics of Background Noise in the Oldest-1 Array Deployed on the Oldest Part of the Pacific Plate
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- Tae-shin Kim
- 1Department of Geophysics, Kangwon National University, Chuncheon, South Korea
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- Ji-hoon Park
- 1Department of Geophysics, Kangwon National University, Chuncheon, South Korea
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- Ji-won Ko
- 1Department of Geophysics, Kangwon National University, Chuncheon, South Korea
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- Se-young Oh
- 1Department of Geophysics, Kangwon National University, Chuncheon, South Korea
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- Michael Witek
- 2Department of Earth and Environmental Sciences, Korea University, Seoul, South Korea
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- Sung-Joon Chang
- 1Department of Geophysics, Kangwon National University, Chuncheon, South Korea
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- Sang-Mook Lee
- 3School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea
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- YoungHee Kim
- 3School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea
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- Hisashi Utada
- 4Earthquake Research Institute, University of Tokyo, Tokyo, Japan
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- Hitoshi Kawakatsu
- 4Earthquake Research Institute, University of Tokyo, Tokyo, Japan
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- Hajime Shiobara
- 4Earthquake Research Institute, University of Tokyo, Tokyo, Japan
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- Takehi Isse
- 4Earthquake Research Institute, University of Tokyo, Tokyo, Japan
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- Nozomu Takeuchi
- 4Earthquake Research Institute, University of Tokyo, Tokyo, Japan
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- Hiroko Sugioka
- 5Ocean-Bottom Exploration Center, Kobe University, Kobe, Japan
Description
<jats:title>ABSTRACT</jats:title> <jats:p>We characterize the sources of background noise recorded by an ocean-bottom seismometer array deployed on the oldest oceanic lithosphere of the western Pacific plate. This igneous oceanic crust is blanketed up to 1000 m cover of sediments, making it a unique place to investigate correlations between sediment thickness and background noise levels in the marine environment. Although the data are limited, we found that the thicker sediments attenuated short-period noise levels and amplified long-period noise levels, in agreement with observations made for seismic arrivals in onshore sedimentary basins. Comparison of the noise levels from our Oldest-1 deployment with those (1) in the western Pacific basin, (2) near the Mariana trench, and (3) offshore New Zealand indicates that the Oldest-1 has the highest noise levels in the double-frequency (secondary) microseism band by up to 7 dB. This result was unexpected given the greater water depths (averaging 5800 m) for the Oldest-1 array. However, even at these great depths, we find a strong correlation between significant wave heights and background noise levels in the short-period microseism band (2–5 s). In addition, the Oldest-1 array was subjected to a great number of intense close typhoons than the other arrays and was proximal to a great number of taller seamounts than the other arrays. Finally, tracking noise source azimuths using station pairs led to the identification of a possible new source for the single-frequency microseism band in the coastal areas of Papua New Guinea and Australia.</jats:p>
Journal
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- Bulletin of the Seismological Society of America
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Bulletin of the Seismological Society of America 113 (4), 1772-1793, 2023-04-27
Seismological Society of America (SSA)
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Details 詳細情報について
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- CRID
- 1360017282467124736
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- ISSN
- 19433573
- 00371106
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- Data Source
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- Crossref
- KAKEN