1.1 These test methods are limited to the determination of the interval velocities from arrival times and relative arrival times of compression (P) waves and vertically (SV) and horizontally (SH) oriented shear (S) seismic waves which are generated near surface and travel down to an array of vertically installed seismic sensors. Two methods are discussed, which include using either one or two downhole sensors (receivers). 1.2 Various applications of the data will be addressed and acceptable procedures and equipment, such as seismic sources, receivers, and recording systems will be discussed. Other items addressed include source-to-receiver spacing, drilling, casing, grouting, a procedure for borehole installation, and conducting actual borehole and seismic cone tests. Data reduction and interpretation is limited to the identification of various seismic wave types, apparent velocity relation to true velocity, example computations, use of Snell's law of refraction, and assumptions. 1.3 There are several acceptable devices that can be used to generate a high-quality P or SV source wave or both and SH source waves. Several types of commercially available receivers and recording systems can also be used to conduct an acceptable downhole survey. Special consideration should be given to the types of receivers used and their configuration to provide an output that accurately reflects the input motion. These test methods primarily concern the actual test procedure, data interpretation, and specifications for equipment which will yield uniform test results. 1.4 All recorded an