干旱区生态环境知识资源中心

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 . Liner’s velocity function estimates an average surface P-wave velocity = 450 m/s and an average porosity ( in the dunes with an average . Al-Shuhail’s velocity function estimates an average surface P-wave velocity and an average velocity-depth gradient in the dunes with an average .