Measurements were made of the shear- and compressional-wave velocities necessary to determine the seismic response of a site on the edge of the San Francisco Bay, California. The shear wave is the most difficult to isolate because of the complications of earlier arriving energy. Downhole and surface measurements yielded shear-wave velocities of 90 to 130 m/sec and compressional-wave velocities of 1,400 m/sec for soft mud. The underlying older sediments had interval shear-wave velocities of 270 to 380 m/sec, increasing with depth. The corresponding P velocities for the older sediments were 1,600 to 1,840 m/sec. The horizontal traction technique of shear-wave generation proved to be the most successful of the methods tested.