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Article citations


Tsugawa, T., Saito, A., Otsuka, Y., Nishioka, M., Maruyama, T., Kato, H., Nagatsuma, T. and Murata, K.T. (2011) Ionospheric Disturbances Detected by GPS Total Electron Content Observation after the Off the Pacific Coast of Tohoku Earthquake. Earth Planets Space, 63, 875-879. https://doi.org/10.5047/eps.2011.06.035

has been cited by the following article:

  • TITLE: Characteristics of Anomalous Radio Propagation before and after the 2011 Tohoku-Oki Earthquake as Seen by Oblique Ionograms

    AUTHORS: Kiyoshi Igarashi, Toshio Tsuchiya, Ken Umeno

    KEYWORDS: Ionospheric Disturbances, Oblique Ionogram, Anomalous Radio Propagation, Atmospheric Gravity Waves

    JOURNAL NAME: Open Journal of Earthquake Research, Vol.9 No.2, March 12, 2020

    ABSTRACT: The characteristics of anomalous radio propagation in the frequency 1 - 30 MHz before and after the 2011 Tohoku-Oki earthquake are firstly revealed by using oblique ionograms for the pass from Wakkanai to Kokubunji which is closest to the epicenter. An oblique ionogram with a wavy-shape-trace was observed at 06:30 UTC on 11 March 2011 after the 2011 Tohoku-Oki earthquake. The velocity of northward-propagating disturbance caused this wavy-shape-trace is estimated to be 130 m/s. This wave-shape-trace shows very clear signature appearing in the oblique ionograms as the characteristic of strong ionospheric disturbances triggered by the earthquake. An oblique ionogram with a steep slopy-shape-trace was observed at 04:45 UTC on 11 March 2011 one hour before the 2011 Tohoku-Oki earthquake. This slopy-shape-trace is investigated as the signatures of preseismic ionospheric anomaly. This anomalous oblique ionogram with a slopy-shape-trace is examined with the slope ratio of virtual height to sweep-frequency, and the difference between monthly median foF2 and hourly value foF2 at Wakkanai and Kokubunji. These features appearing in oblique ionograms suggest that it is useful for studying the signatures of preseismic ionospheric anomaly.