STRUCTURAL INTERPRETATION USING REFRACTION VELOCITIES FROM SEISMIC SURVEYS.

A compressional wave velocity model is presented for the upper few kilometers of Thomson in McDuffie county, Georgia. The velocities were determined from refractions, that is first arrivals, on individual seismic reflection records. The refractions are clear, and it is possible to define the gross structure in addition to the predominant velocity layers of 2.8, 3.7, 4.5 and 6.1 km/s. The observed velocity model implies pronounced variations in thickness of the tertiary, Mesozoic and Paleozoic strata and extreme structural relief of the crystalline basement. The most conspicuous feature shown by the velocity data is a horst, an intrarift uplift of the Precambrian basement.