A traveltime interpretation of the 1978 seismic refraction profile in the Kingdom of Saudi Arabia

Traveltime analysis of the USGS/DGMR-conducted seismic refraction profile in Saudi Arabia is described. The analyzed data consist of reversing and overlapping profiles obtained from six shotpoints extending from the southern Red Sea nearly to the city of Riyadh on the Arabian Shield. Data analysis consisted of the following steps. Primary and secondary arrivals were determined from record sections reduced to 6.0 or 8.0 km/s. The phases were identified as either refracted or reflected waves based on their amplitudes and traveltime behavior. The one-dimensional models (velocity as a function of depth only) to the southwest and northeast of each shotpoint were combined to make preliminary two-dimensional models. Qualitative judgments were made concerning the relative sharpness of the seismic discontinuities on the basis of the apparent amplitude relations of the various phases, and these judgments were used to vary the two-dimensional model.