Brent L. Rosenblad (rosenbladb@missouri.edu), Jonathan Bailey, and Jianhua Li, Department of Civil Engineering, University of Missouri-Columbia

Results are presented from surface wave velocity measurements performed in the Mississippi Embayment to develop shear wave velocity (V_S) profiles of the deep sediments in this region.  Measurements were performed at eleven locations in Arkansas, Tennessee, and Missouri.  Eight of the sites were located adjacent to seismic stations operated by the Center for Earthquake Research and Information (CERI) at the University of Memphis.  This study utilized a unique low-frequency field vibrator that was recently developed as part of the Network for Earthquake Engineering Simulation (NEES) program.  Surface wave energy was actively excited down to frequencies of less than 1 Hz, generating surface waves with wavelengths of 600 m or greater at most sites.  Shear wave velocity (V_S) profiles were developed to depths of over 200 m.  The V_S values typically ranged from approximately 100 m/s near the surface to over 600 m/s at the maximum profiling depths.  Several distinct transitions in V_S values were observed at variable depths among the eleven sites.  An average V_S developed from the eleven sites was in good agreement with V_S models that have been developed for the deep sediments of the Embayment.