3D velocity modeling for mineral exploration via ambient noise tomography

An application of ambient noise tomography (ANT) for mineral exploration near the town of Marathon, Ontario, Canada, is documented. The study area consists of host rocks for platinum group metals and copper. ANT was performed to generate a 3D shear-wave velocity (VS) model for the exploration of Marathon deposits. The ambient noise recordings used were collected using 90 vertical geophones for 26 days. The recordings were used to compute the noise correlation functions and estimate Rayleigh wave phase and group velocity dispersion curves. Then, these dispersion measurements were used for 2D tomography to create 2D velocity maps that were inverted to obtain a 3D VS model. The independently produced VS model shows good agreement with the measured VS from downhole VS logging. Furthermore, the developed 3D velocity model aids in interpretation of the study area that can be helpful for future mineral exploration and for improving understanding of the mineral generation model.