MicroGravity mapping for King Abdulaziz University campus: imaging subsurface

Abstract

A gravity survey was undertaken to cover the King Abdulaziz University’s campus (~ 8 km2) as a pilot project funded from Deanship of Scientific Research (DSR). In the current study, 408 gravity stations were collected using the Scintrex CG5 gravimeter and a DGPS system, covering the whole university’ campus. The aim of this survey is to produce the first microgravity map for the King Abdulaziz University campus and image the subsurface conditions which help in the future constructions. Gravity surveys are carried out for 16 days, nights, and weekends when the campus has less traffic noise. Data were processed using conventional gravity data reduction technique, and then microgravity map for the campus was generated. Data were subject to geophysical filters such as edged detection (e.g., horizontal gradient) and depth estimation (e.g., Euler deconvolution, and 3D inversion) to image the subsurface conditions. Results indicate that bedrock relief surface is located at about 150 m. Some cracks/fractures were traced/detected underneath the surface in various directions. The results also indicate that the university campus is located on high-density rock zones, giving more stability to buildings.