Seismic imaging of the Naga thrust using multiscale waveform inversion

Abstract

This case study images the structural features related to the Naga thrust fault (northeast India) using a combination of multiscale waveform inversion and prestack depth migration (PSDM). The waveform model and the PSDM image complement each other: the former provides a physical-property map (P-wave velocity model) and the latter provides a structural image. The velocity model encompassing the starting model for waveform inversion is constructed using joint inversion of first and reflected traveltimes. The [Formula: see text] data are inverted consecutively in [Formula: see text] bandwidths to yield the final waveform model, which in turn is used for PSDM. The PSDM image and the waveform model are consistent with the lithological interpretation of an inline exploratory well. When interpreted jointly, the PSDM image and the waveform model reveal the presence of a conjugate fault system in the Naga thrust and fold belt.