Full waveform inversion of velocity and temperature based on thermoacoustic equations

ABSTRACT A full-waveform inversion method was proposed to directly estimate subsurface temperature alongside seismic velocity. The approach used thermoacoustic wave equations derived from generalized thermoelastic theory and the adjoint-state method for efficient gradient computation. To guide model updates, the radiation patterns of partial-derivative wavefields induced by perturbation sources were analyzed. A triangle–square model was used to examine parameter crosstalk and evaluate the effectiveness of a stepwise inversion strategy. Synthetic tests on simulated data confirmed the reliability of the inversion process. The results showed that our method accurately recovers velocity and temperature parameters, demonstrating a promising strategy to extract subsurface temperature information from seismic data.