Figure 2. Wave-test data recorded for the purpose of analyzing signal frequency bandwidth, identifying coherent and ambient noise modes and quantifying signal-to-noise character of seismic data across a prospect area. In this example, closely spaced test-data traces have been summed to represent data acquired with a geophone array length of 110 feet (33.5 meters). The apparent velocities of several modes embedded in the test data are labeled in units of feet/second.