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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/21958
Title: Crustal heterogeneity in the 2007 Noto-Hanto earthquake area and its geodynamical implications
Authors: Padhy, Simanchal
Mishra O.P.
Zhao D.
Wei W.
Published in: Tectonophysics
Abstract: To understand the genesis of the 25 March 2007 Noto-Hanto earthquake (Mw 6.6), we determined high-resolution 3-D seismic velocity (Vp and Vs) and Poisson's ratio (σ) images in the epicenter area using 24,698 P-wave and 22,927 S-wave arrival times from 809 earthquakes and 265 sP depth-phase data collected from seismograms of 162 earthquakes beneath the Japan Sea. The sub-oceanic events are relocated accurately by using P-, S- and sP depth-phase arrival time data jointly. Our results demonstrate that the seismic velocity (Vp and Vs) and Poisson's ratio (σ) vary markedly in the source area. In and around the main shock hypocenter, low-velocity and high-σ anomalies are revealed, which are apt for accumulation of differential strain to bring the brittle failure. We infer that the zone with pronounced low-velocity and high Poisson's ratio beneath the source area reflects fluid-related anomalies derived either from the dehydration of the subducting Pacific slab or from permeation of sea-water through deep-seated active faults or both to the main shock hypocenter, which in turn may have facilitated the rupture initiation of the main shock and its aftershock sequence by weakening the overlying seismogenic layer beneath the region. Our study reinforces the concept of fluid-driven earthquakes in the peninsular regions, elsewhere in the world. © 2011 Elsevier B.V.
Citation: Tectonophysics, 509: 55-68
URI: https://doi.org/10.1016/j.tecto.2011.06.002
http://repository.iitr.ac.in/handle/123456789/21958
Issue Date: 2011
Keywords: 2007 Noto-Hanto earthquake
Fluids
Seismic tomography
Slab dehydration
SP depth-phase
ISSN: 401951
Author Scopus IDs: 6701588982
57225351836
7403489801
48261535500
Author Affiliations: Padhy, S., National Geophysical Research Institute, Hyderabad 500007, India, Department of Geophysics, Tohoku University, Sendai 980-8578, Japan
Mishra, O.P., Geo-Seismology Division, Geological Survey of India, Kolkata, India, SAARC Disaster Management Centre, New Delhi, India
Zhao, D., Department of Geophysics, Tohoku University, Sendai 980-8578, Japan
Wei, W., Department of Geophysics, Tohoku University, Sendai 980-8578, Japan
Corresponding Author: Padhy, S.; National Geophysical Research Institute, Hyderabad 500007, India; email: padhys@rediffmail.com
Appears in Collections:Journal Publications [ES]

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