摘要： Coseismic ionospheric disturbances (CIDs) associated with the 2011 Tohoku earthquake off the Pacific coast (Mw 9.0, Tohoku EQ) were examined using total electron content and seismic wave data. A faster CID propagated at ~3.0 km/s only in the west‐southwest, while a slower CID propagated concentrically at 1.2 km/s or slower from the tsunami source area. Taking the propagation speed and oscillation cycle into account, the faster CID was associated with a Rayleigh wave, but the slower CID was associated with an acoustic or gravity wave. The north‐south asymmetry of the CID associated with the Rayleigh wave suggests that the Rayleigh wave did not act as a point source of the acoustic wave because a point source propagating in all directions must produce symmetric CID in all directions. Therefore, a superimposed wave front of acoustic waves was excited by the Rayleigh wave and produced the north‐south asymmetry of the faster CID due to the magnetic inclination effect, which is different from a well‐known north‐south asymmetry of CID excited at the epicenter. On the other hand, above and south of the tsunami source area, the CID with a period of 4 min was excited by a point source located at the tsunami source area because atmospheric waves propagating from a point source produce north‐south asymmetry in the resulting CID. Key Points CID related to Rayleigh wave propagates southward The asymmetry is generated by a superimposed wave front CID related to acoustic resonance occurs above and south of tsunami source area 其他題名： J. Geophys. Res. Space Physics 出版者： Washington: Blackwell Publishing Ltd 出版日期： 2013-02 出處： Journal of geophysical research : Space physics (2013 - Present), 2013-02, Vol.118 (2), p.905-911 資源來源： Wiley Online Library - Journals 版權： 2013. American Geophysical Union. All Rights Reserved. 識別號： ISSN: 2169-9380 識別號： EISSN: 2169-9402 識別號： DOI: 10.1002/jgra.50099
