Crustal Structure Across Cambay Rift Through Receiver Functions

Teleseismic receiver function studies were carried out to probe the crustal and subcrustal structure across the Cambay rift which is a narrow, NNW-SSE trending buried feature in north-western India. Four broadband seismological stations were operated for about two years along a 430km long N-S seismic profile cutting across the rift. In addition, four short-period seismographs were functioning during the same period within the rift. Over 800 teleseismic earthquakes events have been analyzed in this study. Strong P-to-S conversions are observed from the basement and from the Moho at most stations. Synthetic modeling of the receiver functions indicated the crustal thickness to be varying from 31km within the northern segment of the Cambay rift to 37km outside the rift. A thin crust within the rift is consistent with the previous deep seismic sounding studies carried out in the rift. The receiver functions at the broadband stations outside the rift in the Deccan volcanic province do not reflect any signatures of low velocity zones in the crust or at sub-crustal levels related to the Deccan volcanism.