Journal: |
Geophysical Research Letter 2016 No.4
clicks:582 |
Title:
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Author:
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J. Y. Liu, C. H. Chen, Y. Y. Sun, C. H. Chen, H. F. Tsai, H. Y. Yen, J. Chum, J. Lastovicka,Q. S. Yang, W. S. Chen, and S. Wen |
Adress: |
College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing, China |
Abstract:
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In this paper, concurrent/colocated measurements of seismometers, infrasonic systems,magnetometers, HF-CW (high frequency-continuous wave) Doppler sounding systems, and GPS receivers areemployed to detect disturbances triggered by seismic waves of the 11 March 2011 M9.0 Tohoku earthquake. Notime delay between colocated infrasonic (i.e., super long acoustic) waves and seismic waves indicates that thetriggered acoustic and/or gravity waves in the atmosphere (or seismo-traveling atmospheric disturbances,STADs) near the Earth’s surface can be immediately activated by vertical ground motions. The circle method isused to find the origin and compute the observed horizontal traveling speed of the triggered infrasonic waves.The speed of about 3.3 km/s computed from the arrival time versus the epicentral distance suggests that theinfrasonic waves (i.e., STADs) are mainly induced by the Rayleigh waves. The agreements in the travel timeat various heights between the observation and theoretical calculation suggest that the STADs triggered by thevertical motion of ground surface caused by the Tohoku earthquake traveled vertically from the ground to theionosphere with speed of the sound in the atmosphere over Taiwan.
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