Spectral Density Analysis of Total Electron Content Perturbations Associated with Earthquakes

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カテゴリ: 論文誌(論文単位)グループ名: 【A】基礎・材料・共通部門発行日: 2016/05/01タイトル(英語): Spectral Density Analysis of Total Electron Content Perturbations Associated with Earthquakes著者名: Hiroyuki Nakata (Gradu ate School of Engineering, Chiba University), Keigo Abe (Graduate School of Engineering, Chiba University), Atsuki Tokunaga (Graduate School of Engineering, Chiba University), Toshiaki Takano (Graduate School of Engineering, Chiba Un著者名(英語): Hiroyuki Nakata (Graduate School of Engineering, Chiba University), Keigo Abe (Graduate School of Engineering, Chiba University), Atsuki Tokunaga (Graduate School of Engineering, Chiba University), Toshiaki Takano (Graduate School of Engineering, Chiba University), Takuya Tsugawa (National Institute of Information and Communications Technology), Michi Nishioka (National Institute of Information and Communications Technology)キーワード: ionospheric perturbation，total electron content，earthquake，acoustic wave要約(英語): We performed the frequency analysis of time-series data of TEC, and examined the variations of TEC associated with earthquakes. Using Fast Fourier Transform processing, the spectral densities of coseismic TEC variations were calculated. The coseismic variations of TEC were detected in 16 events out of 26 events where the earthquakes larger than M6.4 occurred around Japan since 2000. In most events, the variations at the frequencies of 4.17, 5.21 mHz were observed. The spectral densities reached their maximums about 11 minutes after the earthquake. Since this delay corresponds to the propagation time of acoustic wave from the ground to the ionosphere, it is confirmed that the coseismic variations are due to the acoustic wave generated by the ground/sea surface perturbations. The enhancement of the signal density increases with the magnitude of earthquake and the height of tsunami. Using the enhancement of the TEC variation, the magnitude of wave source can be estimated.本誌: 電気学会論文誌A（基礎・材料・共通部門誌） Vol.136 No.5 （2016） 特集：電磁界を用いた自然災害軽減のための観測・予測・解析技術本誌掲載ページ: 272-277 p原稿種別: 論文／英語電子版へのリンク: https://www.jstage.jst.go.jp/article/ieejfms/136/5/136_272/_article/-char/ja/ Show more