Premium
Seismic evidence for significant crustal thickening beneath Jabalpur earthquake, 21 May 1997, source region in Narmada–Son lineament, central India
Author(s) -
Rai S. S.,
Vijay Kumar T.,
Jagadeesh S.
Publication year - 2005
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 - 10.1029/2005gl023580
Subject(s) - lineament , geology , crust , seismology , seismometer , thickening , fault (geology) , geophysics , tectonics , chemistry , polymer science
We investigate crustal properties beneath the deep crustal (∼35 km) Jabalpur earthquake of 21 May 1997, Narmada‐Son Lineament (NSL), central India, in search of a possible cause of stress accumulation in the region. Teleseismic receiver functions computed at nine digital seismographs along a 250 km long profile suggests Moho downwarp to ∼52 km across the width of the lineament, in contrast with an average 40 km depth elsewhere. In addition, the crust beneath the NSL has higher V p /V s of 1.84 compared to ∼1.73 in the surrounding, suggestive of a high‐density mafic mass at depth that compensates the crustal root, also supported by small topographic variation (200 m) across the lineament. Presence of such an anomalous mass in the deep crust may lead to gravitationally induced stresses in the lower crust that contribute to the failure of rock along the pre‐existing Narmada‐Son fault leading to the earthquake in deep crust.