INTEGRATING HIGH-RESOLUTION REFRACTION DATA INTO NEAR-SURFACE SEISMIC-REFLECTION DATA-PROCESSING AND INTERPRETATION

Shallow seismic reflection surveys commonly suffer from poor data qual ity in the upper 100 to 150 ms of the stacked seismic record because o f shot-associated noise, surface waves, and direct arrivals that obscu re the reflected energy. Nevertheless, insight into lateral changes in shallow structure and stratigraphy can still be obtained from these d ata by using first-arrival picks in a refraction analysis to derive a near-surface velocity model. We have used turning-ray tomography to mo del near-surface velocities from seismic reflection profiles recorded in the Hueco Bolson of West Texas and southern New Mexico. The results of this analysis are interval-velocity models for the upper 150 to 30 0 m of the seismic profiles which delineate geologic features that wer e not interpretable from the stacked records alone. In addition, the i nterval-velocity models lead to improved time-to-depth conversion; whe n converted to stacking velocities, they may provide a better estimate of stacking velocities at early traveltimes than other methods.