Seismo traveling ionospheric disturbances of HF Doppler shift triggered by the 2011 M9.0 Tohoku earthquake observed in Taiwan

M.Y. Chou 996203012@cc.ncu.edu.tw Institute of Space Science, National Central University, Chung-li, Taiwan J.Y. Liu jyliu@jupiter.ss.ncu.edu.tw Institute of Space Science, National Central University, Chung-li, Taiwan A network of digital HF Doppler sounding system in Taiwan is used to study seismo traveling ionospheric disturbances (STIDs) triggered by an earthquake of magnitude 9.0 occurring near the east coast of Honshu (Tohoku area) in Japan on 11 March 2011. Clear STIDs consist of a package of short-period Doppler shifts, which yield vertical ionospheric fluctuations with a maximum velocity of about 120m/s. An angle of arrival analysis and the circle method are use to estimate the propagation velocity and located the STID origin. Results show that the STIDs are excited by the Rayleigh waves, which quickly propagate away from the origin near the reported epicenter with a speed about 2.3-3.3 km/s.