Masw Refraction Reflection Seismograph Borehole Seismic Survey Instrument 24channels Seismometer Engineering Seismograph With Seismic Geophone

MASW is an acronym of Multichannel Analysis of Surface Waves.  It is a seismic exploration technique. It evaluates ground stiffness by measuring shear-wave velocity (Vs) of subsurface in 1-D, 2-D, and 3-D for various types of geotechnical engineering projects in the most common depth range of 0-30 meters. 




MASW first measures seismic surface waves generated from various types of seismic sources-such as sledge hammer-analyzes the propagation velocities of those surface waves, and then finally deduces shear-wave velocity (Vs) variations below the surveyed area that is most responsible for the analyzed propagation velocity pattern of surface waves.  Shear-wave velocity (Vs) is one of the elastic constants and closely related to Young's and shear moduli.  Under most circumstances, Vs is a direct indicator of the ground strength (stiffness) and therefore commonly used to derive load-bearing capacity.




Overall procedure to produce a typical 2D S-velocity (Vs) cross section consists of collecting multichannel seismic records at multiple locations as illustrated below.  Each record then generates a 1-D (depth) velocity (Vs) profile, multiple of which will construct the final 2D cross section.


 
In shallow seismic exploration, the commonly used methods are refracted wave exploration method, reflected wave exploration method and surface wave exploration method. The refracted wave exploration method is a long-term and mature method. It uses a large seismic source, can quickly cover a long distance to detect near-surface targets, and can characterize uplift structures with obvious velocity contrasts. It has the advantages of simple operation and high work efficiency. , the first arrival wave is easy to identify, easy to explain and other advantages, these are incomparable to the reflected wave method.