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Two‐dimensional simulation of ionospheric variations in the vicinity of the epicenter of the Tohoku‐oki earthquake on 11 March 2011
Author(s) -
Shinagawa H.,
Tsugawa T.,
Matsumura M.,
Iyemori T.,
Saito A.,
Maruyama T.,
Jin H.,
Nishioka M.,
Otsuka Y.
Publication year - 2013
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl057627
Subject(s) - epicenter , tec , ionosphere , total electron content , thermosphere , geology , geophysics , seismology , atmospheric sciences , geodesy
Unusual ionospheric variations were observed in the M 9.0 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.