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Seismic imaging of the aftershock zone of the 2001 Mw 7.7 Bhuj earthquake, India
Author(s) -
Mandal Prantik,
Pujol Jose
Publication year - 2006
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 - 10.1029/2005gl025275
Subject(s) - geology , aftershock , seismology , fault (geology) , rift , mafic , seismic tomography , pluton , petrology , tectonics , geochemistry , mantle (geology)
Detailed seismic tomography reveals that the 2001 Mw 7.7 Bhuj earthquake was associated with a 10–14% increase in Vp and Vs and a 10% decrease in Vp/Vs in the 10 to 35 km depth range covering a 2750 km 2 area beneath the aftershock zone. This anomaly could be attributed to the existence of a lithological heterogeneity or a pluton of mafic composition that might have intruded during the rifting in early Jurassic (∼160 Ma). The Banni basin and the Wagad uplift are found to be associated with high velocity intrusive bodies extending from 5 to 35 km depth. A few patches of low Vp and Vs and high Vp/Vs between 10 to 30 km depth have also been detected on the causative 45° south dipping north Wagad fault (NWF) for the 2001 mainshock, which may be attributed to a fluid filled fractured rock matrix.