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High resolutionQ−1estimation based on extension of coda normalization method and its application toP-wave attenuation structure in the aftershock area of the 2005 West Off Fukuoka Prefecture Earthquake (M7.0)

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Title: High resolutionQ−1estimation based on extension of coda normalization method and its application toP-wave attenuation structure in the aftershock area of the 2005 West Off Fukuoka Prefecture Earthquake (M7.0)
Authors: Matsumoto, S. Browse this author
Uehira, K. Browse this author
Watanabe, A. Browse this author
Goto, K. Browse this author
Iio, Y. Browse this author
Hirata, N. Browse this author
Okada, T. Browse this author
Takahashi, H. Browse this author →KAKEN DB
Shimizu, H. Browse this author
Shinohara, M. Browse this author
Kanazawa, T. Browse this author
Keywords: Body waves
Seismic attenuation
Seismic tomography
Wave scattering and diffraction
Issue Date: Nov-2009
Publisher: Oxford University Press
Journal Title: Geophysical Journal International
Volume: 179
Issue: 2
Start Page: 1039
End Page: 1054
Publisher DOI: 10.1111/j.1365-246X.2009.04313.x
Abstract: We developed a method for estimating the seismic-wave attenuation (1/Q) in a seismically active region such as an aftershock area. To estimate the attenuation factor between two adjacent hypocentres, we employed two seismograms recorded at a station and calculate the ratio between two power spectra of direct waves normalized by those in the coda for both the events. The coda normalization of the spectrum and the ratio between the two events minimize the possible influences of sources, sites, instruments and attenuation from the station to the hypocentral area. The 1/Q value can be estimated from the variation of the ratios of event pairs calculated at many stations for various traveltime differences between the even pairs. This method involves double-difference (DD) estimation from the logarithmic power spectra for estimating the 1/Q structure, employing a concept similar to the recently developed ‘DD tomography’ for velocity structures. We applied this method to the aftershock area of the 2005 West Off Fukuoka Prefecture Earthquake (M7.0) in order to investigate the 1/Q structure of P waves. By using the spectra of the seismograms of 1781 events recorded at a dense seismic network deployed around the aftershock area, we obtained the spatial variation of the 1/Q value in this region. The 1/Q distribution thereby obtained suggests that there exists a high-attenuation region around the edge of the main shock fault, which could correspond to the segment boundary between the earthquake fault and the adjacent faults. In addition, we found that the initiation points of the main shock and aftershocks were located in a low-attenuation region.
Rights: This article has been accepted for publication in Geophysical Journal International ©:The Authors 2009 Published by Oxford University Press on behalf of The Royal Astronomical Society All rights reserved.
Type: article
URI: http://hdl.handle.net/2115/57958
Appears in Collections:理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: 高橋 浩晃

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