High-Precision Repeat Gravity Measurements In Riyadh Using Fgl Absolute Gravimeter, Potential Applications For Saudi Arabia

English Abstract:

High-precision repeat Absolute Gravity measurements are lacking for the Kingdom of Saudi Arabia, though there is an urgent need for such measurements considering their scientific importance, tectonic implications and also the size of the country. Presently there is no IGSN71 station within the Kingdom. Not only that; the base and baseline stations established by USGS, through network tie with IGSN stations in Africa way back in 1985, have also become extinct. Considering these aspects, we undertook repeat Absolute Gravity measurements by deploying FGL Absolute Gravimeter, for one locale on the Arabian Platform – King Saud University (KSU) Riyadh, Saudi Arabia. These measurements were continued since June 2008 through December 2014, which consists of a total of 310+ processed repeat data sets, displaying a set scatter of 1.87 – 4.52 μGal, where, the measuring precision is found to range between 0.29 – 0.52 μGal. Its best determined value at the King Saud University Absolute Gravity Base (called; KSU-AGB1) is: 978780044.50 µGal, Lat: 24.72167N, Long: 46.61722E, Elevation: 650.00 m, Set Scatter: 2.77 µGal, Measurement Precision: 0.57 µGal, , Total Uncertainty: 10.53 µGal. Plate I illustrates a typical display record for the FGL Absolute Gravimeter monitored on 7 January 2015 at KSU-AGB1. We recommend that the absolute gravity value reported here for KSU-AGB1 may be considered as the National Gravity Base for Saudi Arabia, and the Absolute Gravity Network in the country may ultimately be linked to this Base value.