Application of surface waves for detecting lateral variations: buried inclined plane

ABSTRACT In this paper, using synthetic and real data, we tested the capability of surface wave‐based methods for detecting subsoil lateral variations across an inclined slope. Simplified soil structures at different inclination angles were considered following an advanced 2D finite‐element modelling approach. Different values of inclination angle (10°–170° at 10° steps), spatial sampling rate and synthetic array length were used in different subsoil models to see the effects. It was found that, as low inclination angles (smaller than 40° with respect to the horizontal axis) are not detectable using the surface wave methods based on offset‐phase angle ( X –ϕ), such methods are not able to correctly recognize the location of possible lateral variations at such inclination angles. On the other hand, for intermediate inclination angles (i.e. between 40° and 140°), the X –ϕ approach was successfully used to determine the exact location of the lateral variations for a wide range of frequencies, thereby opening new perspectives for the application of surface waves for detecting laterally inclined layers.