Analysis of Time-Depth Data in Sand Dunes from the Empty Quarter Desert of Southeastern Saudi Arabia

Abstract

Theoretical and field studies show that P-wave velocity increases continuously with depth in unconsolidated sands. Many analytical and empirical models have been proposed to account for this phenomenon in near-surface layers. This study presents five new uphole data sets acquired in sand dunes located in the Empty Quarter (Rub’ Al-Khali) Desert in southeastern Saudi Arabia. Furthermore, the study compares the following velocity-depth functions: constant-velocity, Al-Shuhail, and Liner by fitting them to these data sets in addition to the sand curve data set. The constant-velocity function estimates an average P-wave velocity equal to 641 m/s in the dunes with an average sum of squared errors (SSE) = 0.00101. Liner’s velocity function estimates an average surface P-wave velocity = 450 m/s and an average porosity (ϕ) = 38.33 % in the dunes with an average SSE = 0.000133. Al-Shuhail’s velocity function estimates an average surface P-wave velocity =25.78m/s and an average velocity-depth gradient =662m-1/3 in the dunes with an average SSE = 0.0000877.