Seismic imaging of the Naga thrust using multiscale waveform inversion

摘要

This case study images the structural features related to theNaga thrust fault northeast India using a combination ofmultiscale waveform inversion and prestack depth migrationPSDM. The waveform model and the PSDM image complementeach other: the former provides a physical-propertymap P-wave velocity model and the latter provides a structuralimage. The velocity model encompassing the startingmodel for waveform inversion is constructed using joint inversionof first and reflected traveltimes. The 4–8-Hz dataare inverted consecutively in 1-Hz bandwidths to yield the finalwaveform model, which in turn is used for PSDM. ThePSDM image and the waveform model are consistent withthe lithological interpretation of an inline exploratory well.When interpreted jointly, thePSDMimage and the waveformmodel reveal the presence of a conjugate fault system in theNaga thrust and fold belt.