Body Wave Analyses of Strain Seismograms Observed at Erimo, Hokkaido, Japan
Title Body Wave Analyses of Strain Seismograms Observed at Erimo, Hokkaido, Japan Author(s) KASAHARA, Minoru; SASATANI, Tsutomu Citation Journal of the Faculty of Science, Hokkaido University. Series 7, Geophysics, 8(1), 83-108 Issue Date 1986-02-26 Doc URL http://hdl.handle.net/2115/8754 Type bulletin (article) File Information 8(1)_p83-108.pdf Instructions for use Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP Jour. Fac. Sci., Hokkaido Univ., Ser. VII (Geophysics), Vol. 8, No.1, 83-108, 1986. Body Wave Analyses of Strain Seismograms Observed at Erimo, Hokkaido, Japan Minoru Kasahara Research Center for Earthquake Prediction, Faculty of Science, Hokkaido University, Sapporo 060, Japan and Tsutomu Sasatani Department of Geophysics, Faculty of Science, Hokkaido University, Sapporo 060, Japan (Received November 25, 1985) Abstract At the Erimo Geophysical Observatory (EGO) a digital recording system has been introduced on July, 1976 into the Earth strain measurements in order to use the fused quartz extensometer of 30 m long as a seismometer. The body wave parts of the strain seismograms from 14 earthquakes with magnitudes ranging from 4.7 to 7.7 recorded by the system were compared with the synthetic strain seismograms generat ed by a point shear dislocation in an infinite homogeneous medium. The waveform and amplitude of the observed strain seismogram could be well explained by the synthetic one calculated for appropriate source parameters deduced from the conven tional method. Based on this result it can be shown that the period of the observed S-wave approximately represents the source process time of an earthquake and the S-wave amplitude is proportional to the seismic moment of the event.
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