Incessant excitation of the Earth's free oscillations

• Nawa Kazunari

  Department of Earth and Planetary Sciences, Nagoya University

• Suda Naoki

  Department of Earth and Planetary Sciences, Nagoya University

• Fukao Yoshio

  Earthquake Research Institute, University of Tokyo

• Sato Tadahiro

  National Astronomical Observatory

• Aoyama Yuichi

  The Graduate University for Advanced Studies

• Shibuya Kazuo

  National Institute of Polar Research

抄録

We, for the first time, report the evidence of incessant excitation of the Earth's free oscillations, mainly the fundamental spheroidal modes in a frequency range from 0.3 to 5 mHz, based on the three year record of a superconducting gravimeter at Syowa Station, East Antarctica. The frequency-time spectrogram of this record is striped by more than 30 lines at nGal level parallel to the time axis, mostly corresponding to the fundamental spheroidal modes. This spectrogram is characterized by relatively efficient excitation of gravest fundamental modes, enhancement of signal intensities in the austral winter and amplification of signal in the frequency band from 3 to 4 mHz. Assuming that earthquakes are only the sources for the free oscillations, we calculate the synthetic spectrograms, which have not shown such a series of parallel lines as observed. The result of this synthetic test and characteristics of the observed spectrogram suggest that the mode signals we found are not of earthquake origin. We tentatively suggest atmospheric or oceanic origin for this newly discovered phenomenon of the solid Earth.

収録刊行物

• Ｅａｒｔｈ，　Ｐｌａｎｅｔｓ　ａｎｄ　Ｓｐａｃｅ

  Ｅａｒｔｈ，　Ｐｌａｎｅｔｓ　ａｎｄ　Ｓｐａｃｅ 50 (1), 3-8, 1998

  地球電磁気・地球惑星圏学会 、公益社団法人 日本地震学会、特定非営利活動法人 日本火山学会、日本測地学会、日本惑星科学会

キーワード

• Space and Planetary Science
• Geology

詳細情報

• CRID: 1390282681485617536
• NII論文ID: 10002205455
• NII論文ID: 130003955856
• NII書誌ID: AA11211921
• DOI: 10.1186/bf03352080
• ISSN: 18805981
• ISSN: 13438832
• ISSN: http://id.crossref.org/issn/13438832
• Web Site: https://link.springer.com/content/pdf/10.1186/BF03352080.pdf
• Web Site: https://link.springer.com/article/10.1186/BF03352080/fulltext.html
• Web Site: http://link.springer.com/content/pdf/10.1186/BF03352080
• 本文言語コード: en
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
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