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M-w dependence of the preseismic ionospheric electron enhancements

Heki_Enomoto_JGR2015.pdf4.34 MBPDF見る/開く

タイトル: M-w dependence of the preseismic ionospheric electron enhancements
著者: Heki, K. 著作を一覧する
Enomoto, Y. 著作を一覧する
キーワード: GNSS
preseismic enhancement
geomagnetic field
発行日: 2015年 8月
出版者: American Geophysical Union
誌名: Journal of geophysical research-space physics
巻: 120
号: 8
開始ページ: 7006
終了ページ: 7020
出版社 DOI: 10.1002/2015JA021353
抄録: Ionospheric electron enhancement was reported to have occurred similar to 40min before the 2011 Tohoku-oki (M(w)9.0) earthquake, Japan, by observing total electron content (TEC) with Global Navigation Satellite Systems receivers. Their reality has been repeatedly questioned due mainly to the ambiguity in the derivation of the reference TEC curves from which anomalies are defined. Here we propose a numerical approach, based on Akaike's information criterion, to detect positive breaks (sudden increase of TEC rate) in the vertical TEC time series without using reference curves. We demonstrate that such breaks are detected 25-80min before the eight recent large earthquakes with moment magnitudes (M-w) of 8.2-9.2. The amounts of precursory rate changes were found to depend upon background TEC as well as M-w. The precursor times also showed M-w dependence, and the precursors of intraplate earthquakes tend to start earlier than interplate earthquakes. We also performed the same analyses during periods without earthquakes to evaluate the usefulness of TEC observations for short-term earthquake prediction.
資料タイプ: article
出現コレクション:雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

提供者: 日置 幸介


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