Investigation of Ionospheric and Magnetic Response during the 2011 Tohoku Earthquake Using Ground Based Measurement

Abstract

This paper investigates co-seismic and post-seismic ionospheric and magnetic disturbances during the M9.0, 11 March 2011 Tohoku earthquake. The investigation collects data from two sources which are the GEONET GPS stations located in the near zone of the epicenter and the MAGDAS stations located near and far from the epicenter. Three types of ionospheric disturbances were detected: direct acoustic wave (894m/s), gravity wave from a propagating Tsunami (226 m/s), and secondary wave from the Rayleigh surface wave (2862 m/s). The directivity of the wave propagation was found to be northward from the epicenter. In addition, magnetic disturbances with period ranging from 4-6 min were also found near the epicenter. These magnetic field disturbances were associated with the short-period ionospheric disturbances induced by the direct acoustic wave from the epicenter.