<p><p><strong>References:<br></strong><em> Sheu et al. (1986)<br>SHRP 2-Phase I Technology Assessment (2008)</em></p><p><strong>Method Summary</strong></p><p>Spectral analysis of surface wave (SASW) method is a non-destructive, in-situ measurement of the shear wave velocity. Geophones and a wave propagation source are placed on the site’s surface. The time is evaluated for the direct, reflected, and refracted surface waves to arrive to the geophone from the source. A shear wave velocity profile is generated from this information. Soil layering and the Young’s modulus of each layer can be determined from this profile. The wave velocity can then be used to determine the Cyclic Stress Ratio which evaluates liquefaction resistance.</p><p><strong>Accuracy and Precision</strong></p><p>SASW is generally regarded as an accurate and precise test.</p><p><strong>Adequacy of Coverage</strong></p><p>One test using SASW is able to cover a large area.</p><p><strong>Implementation Requirements </strong></p><p>This method requires experience-based judgment to determine if obtaining reasonable results and to interpret the data. This test also requires specialized equipment.</p><p><strong>General Comments</strong></p><p>The shear wave velocity of the soil is an important parameter for assessing a site’s resistance to liquefaction and lateral spreading resulting from a seismic event. This will have an impact on the site’s ability to support its service load.</p></p>