Two-dimensional Crustal Velocity Structure along Hirapur-Mandla Profile from Seismic Refraction and Wide-angle Reflection Data

Abstract

The seismic velocity structure of the upper and lower crusts along Hirapur-Mandla profile was obtained by 2-D forward modeling of the refraction and wide-angle reflection data. Digitized record sections of the analog data were utilized for delineation of the crustal velocity model across the Vindhyan basin and the Narmada-Son lineament by travel-time modeling and qualitatively matching the amplitudes of synthetic seismograms with seismic record sections. An interface at a depth of 8 km has been traced from wide-angle reflection data of shot points 160 and 235 between Jabalpur and Mandla. The wide-angle reflection phase from crust-mantle boundary is very prominent in all the seismic record sections of shot points 0, 40, 80, 120 and 235. The Moho horizon along the entire study area was continuously traced, depicting an upwarp between Katangi and Jabalpur below the Narmada-Son lineament. The three faults inferred near Narsinghgarh, Katangi and Jabalpur divide the crust into four blocks. The number of faults and displacement patterns along them, depicted along the profile, indicates that block tectonics appear to be active in this region throughout the geological history.

2-D Crustal Velocity Structure Along Hirapur-Mandla Profile in Central India: An Update

“…These results were based on the modeling of travel-time data only. MURTY et al (1998) derived the first 2-D crustal seismic velocity model by considering the travel-time modeling and amplitude analysis utilizing the digitized record sections. In that paper, we have modeled only the long and continuous wideangle reflection phases.…”

“…1). The interpreted velocity boundaries have then been extended to propose a density model along this profile for a better constrained interpretation and as an update to the 2-D velocity model presented earlier (MURTY et al, 1998). The present study forms a part of the integrated geophysical modeling of the Narmada region.…”

“…

The 2-D crustal velocity model along the Hirapur-Mandla DSS profile across the Narmada-Son lineament in central India (MURTY et al, 1998) has been updated based on the analysis of some short and discontinuous seismic wide-angle reflection phases. Three layers, with seismic velocities of 6.5-6.7, 6.35-6.40 and 6.8 km s )1 , and upper boundaries located approximately at 8, 17 and 22 km depth respectively, have been identified between the basement (velocity 5.9 km s )1 ) and the uppermost mantle (velocity 7.8 km s )1 ).

…”

Tectonic Control on Drainage Network Evolution in the Upper Narmada Valley: Implication to Neotectonics

“…Pleistocene sedimentary terraces in SNF zone are tilted 20-25 ∘ in the tract Hardi-Jabalpur and are also displaced 10-15 m near Navagram [15]. The seismic structure and existence of sedimentary basin of SONATA zone is interpreted by Murty et al [16] and Kumar et al [17] using 2D crustal seismic velocity models and 2D gravity modeling by Mishra, [18], Verma and Banerjee [19], Sridhar and Tewari, [20] and Mishra et al [21]. The high Bouguer gravity anomaly between Jabalpur and Mandla suggests localized uplift of SNSF and the presence of a magmatic body at different depths.…”

“…The high Bouguer gravity anomaly between Jabalpur and Mandla suggests localized uplift of SNSF and the presence of a magmatic body at different depths. Murty et al [16] have concluded that the upper Vindhyans directly overlie the Archaean basement between Hirapur and Narsinghgarh. Between Narsinghgarh and Katangi, the Vindhyan basin consists of the upper and lower Vindhyans [22].…”