Subcrustal Low Velocity Layers in Central India and their Implications

摘要: A 2-D subcrustal velocity model for the central Indian continental lithosphere has been derived by travel time and relative amplitude modeling of a digitally normalized analog seismic record section Hirapur-Mandla DSS profile, using ray-tracing technique. Some prominent wave groups with apparent velocities slightly higher than Moho reflection phase (PMP) are identified on sections assembled reduction 6 km s−1. We interpret these phases as wide-angle reflections from lithospheric boundaries. Comparison synthetic seismograms observed shows that cannot be explained either multiples or P-to-S converted (PMS) Moho. Subcrustal models increase single low layer (LVL) also do not provide satisfactory fit. infer two alternate LVLs (velocity 7.2 s−1), separated 6-km thick high 8.1 can satisfy both times amplitudes. The modeled at depths 49, 51, 57 60 km. It is inferred in region lamellar structure varying structural mechanical properties. alternating LVLs, occurring relatively shallow below Moho, may associated zones weakness lower viscosity suggesting continued mobility, possible thermal source upper mantle. This explains heat flow values region.