Full-waveform ambient noise inversion on finite domains

SUMMARY Seismic ambient noise tomography has been a powerful tool for seismic imaging, but most existing approaches fail to accurately predict detailed correlation waveforms in the presence of spatially heterogeneous noise distributions. Full-waveform ambient noise inversion allows for high-resolution waveform-based inversion even in substantially heterogeneous noise fields. Unfortunately, the computational cost of this approach is constrained by the noise distribution, rather than the inversion domain: global-scale applications are viable, but smaller scale applications require a modified approach. We present a general finite-domain full-waveform ambient noise inversion methodology, providing approximation mechanisms for treating out-of-domain propagation from distant noise sources. This makes the problem tractable on much smaller domains. In a numerical example, we demonstrate that this approach enables inversion for both structure within a chosen domain and approximate noise source distribution outside it.