Velocity of Shear Waves through Unconsolidated Materials

The elastic properties of the unconsolidated materials which cover most of the earth are, in general, unknown. In this paper, an attempt was made to measure, in the field, the shear and compressional wave velocities, with the emphasis on those for shear waves. For this purpose,'a simple source was devised which produced fairly pure shear waves. A portable refraction seismograph of standard design was used to record the seismic waves. With the extremely short spreads used, normally from 40 to 80 feet, it was found that the shear wave velocities for a variety of unconsolidated materials ranged from 300 ft/sec to 825 ft/sec. The results obtained were compared, whenever possible, to previous work done on similar types of materials. These comparisons generally showed good agreement when the differences in materials and methods of measurement were taken into consideration.