Tracking scattered signals in the acoustic coda using independent component analysis in a topographically complex setting

Abstract

We outline a method using gradient flow independent component analysis (ICA) to separate signals comprising the coda in a topographically complex setting.We also identify the sources of scattered signals by tracking signal backazimuths over time. The gradient flow ICA method is shown to effectively separate signals in the acoustic coda. The method correctly identifies the backazimuth of the first arrival from two 800 kg TNT equivalent explosions as well as subsequent signals scattered by the surrounding topography. Circular statistics is used to analyse the variance, mean and uniformity of calculated backazimuths. These results have strong implications for understanding the acoustic wavefield by identifying scatterers and inverting for atmospheric conditions.