Deep Shear Wave Velocity Profiles from Surface Wave Measurements in the Mississippi Embayment

Abstract

Shear wave velocity (V S ) profiles to depths of approximately 200 m were developed from active‐source surface wave velocity measurements in the Mississippi Embayment region of the Central United States. Soil deposits in this region are hundreds of meters thick, but are poorly characterized at depths below 60 m . Measurements were performed at five locations in Arkansas and Tennessee with a maximum distance between sites of approximately 130 km . The median V S profile calculated from the five profiles is in good agreement with a generic reference V S profile for the Mississippi Embayment that has been used in recent site response studies. The near‐surface V S profiles at the five sites were remarkably consistent with average shear wave velocities in the top 30 m (V S 30 ), varying by less than 10%. Increasing variability between the V S profiles was observed at greater depths. The variability between V S profiles was shown to be correlated with changes in lithology at two of the sites where nearby lithologic information was available.