|Surface wave is a seismic wave which travels near the surface of the earth.
The property of the surface seismic wave contains useful information about underground material. Imagine if the ground has an unconsolidated layer, it rocks slowly in response to seismic impact. On the other hand, if the ground is made of solid rock, it trembles with very fast vibration. This property of the ground, slow rocking and fast vibration, is called frequency response.
The Multi-Array Surface Wave (MASW) Method measures the seismic wave travelling near the surface and analyses for the frequency response of underlying ground. It is capable of resolving the S-wave velocity structure down to 50 metres deep.