Improvement of H/V technique by rotation of the coordinate system

In this work we investigate the application of the rotation of the coordinate system before applying denoising techniques aimed at improving the H/V spectral ratio for seismic site effects estimation. By this rotation, one can detect the direction of maximum and minimum matching between any couple of orthogonal H/V ratios. The direction of minimum matching should represent the direction of maximum anisotropy of the surface layer or a directional noise. To further improve the method, singular spectrum analysis and WASEE techniques are then applied.