Surface Wave Dispersion Analysis (MASW/SASW/ReMI)
Surface waves are familiar as either ocean waves, ripples on a pond , or the ground motion experienced during an earthquake. Also known as Rayleigh waves, these waves have a characteristic known as dispersion, in that the speed with which a surface wave travels is dependent on its frequency. Geophysicists can use the dispersive nature of Rayleigh waves to determine rock properties, and in some cases, look for subsurface voids and fractures. Most commonly, surface waves are used to determine a shear wave velocity profile, usually to a depth of 30 meters, which is then used for building foundation design. Surface wave geophysical methods are accepted by the International Building Code (IBC) in lieu of drilling boreholes. The common variations on surface wave dispersion analysis are known as SASW (Spectral Analysis of Surface Waves), MASW( Multichannel Analysis of Surface Waves), and ReMi (Refraction Microtremor). ZAPATA has experience in acquiring and analyzing surface wave data using all of these methods.
