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HF Doppler observations of acoustic waves excited by the earthquakeIonospheric disturbances caused by the earthquake of a relatively small and large epicentral distance have been detected by a network of HF-Doppler sounders in central Japan and Kyoto station, respectively. The HF-Doppler data of a small epicentral distance, together with the seismic data, have been used to formulate a mechanism whereby ionospheric disturbances are produced by the Urakawa-Oki earthquake in Japan. Comparison of the dynamic spectra of these data has revealed experimentally that the atmosphere acts as a low-pass filter for upward-propagating acoustic waves. By surveying the earthquakes for which the magnitude M is larger than 6.0, researchers found the ionospheric effect in 16 cases of 82 seismic events. As almost all these effects have occurred in the daytime, it is considered that it may result from the filtering effect of the upward-propagating acoustic waves.
Document ID
19860018312
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Ichinose, T.
(Doshisha Univ. Kyoto, Japan)
Takagi, K.
(Doshisha Univ. Kyoto, Japan)
Tanaka, T.
(Toshiba Electric Co. Nagoya, Japan)
Okuzawa, T.
(University of Electro-Communications Tokyo, Japan)
Shibata, T.
(Doshisha Univ. Kyoto, Japan)
Sato, Y.
(Tohoku Univ. Sendai, Japan)
Nagasawa, C.
(Tokyo Metropolitan Univ. (Japan), United States)
Ogawa, T.
(Kyoto Univ. Japan)
Date Acquired
August 12, 2013
Publication Date
December 1, 1985
Publication Information
Publication: International Council of Scientific Unions Handbook for MAP, Vol. 18
Subject Category
Geophysics
Accession Number
86N27784
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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