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Long‐period seismic amplification in the Kanto Basin from the ambient seismic field
Author(s) -
Denolle Marine A.,
Miyake Hiroe,
Nakagawa Shigeki,
Hirata Naoshi,
Beroza Gregory C.
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl059425
Subject(s) - geology , seismometer , seismology , structural basin , seismic noise , environmental seismic intensity scale , period (music) , microseism , vertical seismic profile , borehole , seismic wave , peak ground acceleration , sedimentary basin , ground motion , geomorphology , geotechnical engineering , physics , acoustics
Tokyo, like many seismically threatened cities, is situated atop a sedimentary basin that has the potential to trap and amplify seismic waves from earthquakes. We study amplification in the Kanto Basin by exploiting the information carried by the ambient seismic field. We use 375 seismic stations from the high sensitivity seismograph network across central Honshu as virtual sources and 296 seismic stations of the Metropolitan Seismic Observation network shallow borehole seismometers within the basin as receivers to map the basin response. We find a linear relationship between ground motion and basin depth at periods of 2–10 s that could be used to represent 3‐D basin effects in ground motion prediction equations. We also find that the strength of basin seismic amplification depends strongly on the direction of illumination by seismic waves.