3D Velocity Modelling for Mineral Exploration via Ambient Noise Tomography

Abstract

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