Long-distance propagation of ionospheric disturbance generated by the 2011 off the Pacific coast of Tohoku Earthquake

Chen, C. H.; Saito, Akinori; Lin, Charles; Liu, J. Y.; Tsai, Ho‐Fang; Tsugawa, Takuya; Otsuka, Yuichi; Nishioka, Michi; Matsumura, M.

doi:10.5047/eps.2011.06.026

Cited by 56 publications

(50 citation statements)

References 16 publications

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“…The sudden TEC depletions in this event were investigated in detail by Saito et al (2011). Chen et al (2011) studied the detail characteristics of the zonally-extended TEC structures (II) which were also observed in Taiwan more than 2,500 km distance from the ionospheric epicenter in the southwest direction. The short-period oscillations in the vicinity of the epicenter (V) were investigated based on the GPS-TEC observations and numerical simulations .…”

Section: Summary and Discussionmentioning

confidence: 99%

Ionospheric disturbances detected by GPS total electron content observation after the 2011 off the Pacific coast of Tohoku Earthquake

et al. 2011

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All the details of ionospheric disturbances following the 2011 Tohoku Earthquake were first revealed by the high-resolution GPS total electron content observation in Japan. The initial ionospheric disturbance appeared as sudden depletions following small impulsive TEC enhancements ∼7 minutes after the earthquake onset, near the epicenter. Then, concentric waves appeared to propagate in the radial direction with a velocity of 138-3,457 m/s. Zonally-extended enhancements of the TEC also appeared in the west of Japan. In the vicinity of the epicenter, short-period oscillations with a period of ∼4 minutes were observed. This paper focuses on the concentric waves. The concentric pattern indicates that they had a point source. The center of these structures, termed the "ionospheric epicenter", was located about 170 km from the epicenter in the southeast direction. According to the propagation characteristics, these concentric waves could be caused by atmospheric waves classified into three types: acoustic waves generated from a propagating Rayleigh wave, acoustic waves from the ionospheric epicenter, and atmospheric gravity waves from the ionospheric epicenter. The amplitude of the concentric waves was not uniform and was dependent on the azimuth of their propagation direction, which could not be explained by previously-proposed theory.

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Section: Summary and Discussionmentioning

confidence: 99%

Ionospheric disturbances detected by GPS total electron content observation after the 2011 off the Pacific coast of Tohoku Earthquake

et al. 2011

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“…The instrumental biases of the satellites and the receivers were estimated and subtracted from the observed data by the method of Otsuka et al (2002). An outline of the ionospheric variations detected by GEONET after the 2011 off the Pacific coast of Tohoku Earthquake has been given by Tsugawa et al (2011), and the ionospheric variations that propagated over a long distance were studied by Chen et al (2011).…”

Section: Observationmentioning

confidence: 99%

Acoustic resonance and plasma depletion detected by GPS total electron content observation after the 2011 off the Pacific coast of Tohoku Earthquake

et al. 2011

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Two-dimensional structures of the ionospheric variations generated by the acoustic resonance between the ground surface and the lower thermosphere was observed for the first time near the epicenter after the M 9.0 Tohoku earthquake on March 11, 2011. A short-period oscillation of total electron content was observed by a GPS receiver array after the earthquake for four hours in the vicinity of the epicenter. It was centered in the east of the epicenter where the tsunami was estimated to commence. The frequency of the dominant mode of the oscillation was 4.5 mHz, 222 seconds of period, while there were minor oscillations whose frequency were 3.7 mHz and 5.3 mHz. These periods are consistent with the periods of the acoustic resonance between the ground surface and the lower thermosphere, predicted by a numerical model. The amplitude of the TEC oscillation showed a gradual change of the amplitude. The two-dimensional distributions of TEC variations generated by this resonance had wave frontal structures that extended from northwest to southeast. The resonant oscillation of the TEC was accompanied by a depletion of TEC whose duration was about 60 minutes. The area of this depletion also centered on the epicenter.

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“…In the M9.0 Tohoku-oki earthquake on 11 March 2011, horizontal wavelike structures of TEC (total electron content) variations were detected by a dense GPS receiver network in Japan [e.g., Chen et al, 2011;Saito et al, 2011;Tsugawa et al, 2011;Astafyeva et al, 2011;Heki, 2011;Liu et al, 2011;Matsumura et al, 2011;Kakinami et al, 2012]. Those studies suggest that the acoustic-gravity waves generated by the sea surface uplift propagate upward to the ionospheric region, causing ionospheric oscillation, and that the center of the ionospheric wave source is located at about 100-150 km east or southeast of the epicenter.…”

Section: Introductionmentioning

confidence: 99%

Two‐dimensional simulation of ionospheric variations in the vicinity of the epicenter of the Tohoku‐oki earthquake on 11 March 2011

Shinagawa

Tsugawa

Matsumura

et al. 2013

Geophysical Research Letters

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Unusual ionospheric variations were observed in the M9.0 Tohoku‐oki earthquake on 11 March 2011. Among various kinds of features in the ionosphere, significant depletion of total electron content (TEC) near the epicenter was observed after the earthquake. Although previous studies have suggested that the coseismic ionospheric variations are associated with atmospheric perturbation caused by vertical displacement of the sea surface, the mechanism of the TEC depletion has not been fully understood. In this paper, a two‐dimensional nonlinear nonhydrostatic compressible atmosphere‐ionosphere model is employed to investigate the ionospheric variations in the vicinity of the epicenter. The simulation results reveal that an impulsive pressure pulse produced by a sudden uplift of the sea surface leads to local atmospheric expansion in the thermosphere and that the expansion of the thermosphere combined with the effect of inclined magnetic field lines in the ionosphere causes the sudden TEC depletion above the epicenter region.

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Long-distance propagation of ionospheric disturbance generated by the 2011 off the Pacific coast of Tohoku Earthquake

Cited by 56 publications

References 16 publications

Ionospheric disturbances detected by GPS total electron content observation after the 2011 off the Pacific coast of Tohoku Earthquake

Ionospheric disturbances detected by GPS total electron content observation after the 2011 off the Pacific coast of Tohoku Earthquake

Acoustic resonance and plasma depletion detected by GPS total electron content observation after the 2011 off the Pacific coast of Tohoku Earthquake

Two‐dimensional simulation of ionospheric variations in the vicinity of the epicenter of the Tohoku‐oki earthquake on 11 March 2011

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