MULTICHANNEL   ANALYSIS OF SURFACE WAVES (MASW)

Multichannel Analysis of Surface Waves (MASW) relies on the study of surface waves in the ground. The MASW technique allows two-dimensional Vs sections, that is the shear wave velocity, to be gotten.

Acquisition geometry depends on the enlisted requirements in lateral resolution and target depth. The acquisition can be adapted in a way such that the data can be valuable and used both for MASW and refraction seismic processing.

It is essential to optimize the choice of the source as a function of target depth, ambient noise and access to the survey site.

Most surveys conducted can be measured using a seismic shotgun or a with the use of sledgehammer, but more powerful sources can be mobilized (weight drops, explosives).

Simultaneous acquisitions of refraction seismology and MASW give information on both Vp and Vs. Most geotechnical parameters can be expressed as a function of these two velocities and the density of the ground. This technique is mainly applied (but not limited to) in the following areas:

• Soil cavity/Void mapping

• Soil stiffness studies

• Rockhead profiling/Bedrock mapping

• Determine weathering/Fracturation in rocks

• Grouting evaluation

• Landfill studies

• Calculation of building design parameters

• Seismic site characterization as per IBC/Eurocode 8

• Mapping of geological structures

• Estimation of geotechnical parameters & Vs30