Multichannel analysis of surface waves (MASW)—active and passive methods

The conventional seismic approaches for near-surface investigation have usually been either high-resolution reflection or refraction surveys that deal with a depth range of a few tens to hundreds meters. Seismic signals from these surveys consist of wavelets with frequencies higher than 50 Hz. The multichannel analysis of surface waves (MASW) method deals with surface waves in the lower frequencies (e.g., 1–30 Hz) and uses a much shallower depth range of investigation (e.g., a few to a few tens of meters).