ORIGINAL PAPER MicroGravity mapping for King Abdulaziz University campus: imaging subsurface Essam Aboud 1,2 & Nabil El‐Masry 1,3 & Sabahuddin Ahmed 1 Received: 8 June 2018 /Accepted: 29 October 2018 /Published online: 13 November 2018 # Saudi Society for Geosciences 2018 Abstract A gravity survey was undertaken to cover the King Abdulaziz University’ s campus (~ 8 km 2 ) 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 micro- gravity map for the King Abdulaziz University campus and image the subsurface conditions which help in the future construc- tions. 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. Keywords MicroGravity . King Abdulaziz University . Jeddah . Saudi Arabia Introduction As a non-destructive geophysical surveying technique, the gravity method is a passive cost-effective technique where energy is not required to acquire data. Gravity surveying, in general, gives information about lateral rock density distribu- tion with depth that are attributed to changes in subsurface structures and lithologies. The main objective for conducting a microgravity survey within the campus of King Abdulaziz University (KAU) is to obtain an overall image of its subsur- face geologic settings (Farhi et al. 2016; Saibi 2018). KAU’ s campus (about 8 km 2 ) is located a cross road-way between some surrounding provinces (e.g., Al-solymania, Faihaa, Al-Naseem, Al-Gamaa, Mecca, etc.). This results in high traffic noise all day inside the campus. To overcome this problem, we recorded gravity measurements at nights and weekends only. In discrete 16 days, we collected 408 gravity stations covering the whole university campus with some gaps due to inaccessible areas (e.g., security buildings, current con- structions). During the whole survey, we used the Scintrex CG5 gravimeter to acquire gravity data. On the other hand, the GPS station locations were corrected using the facility of the Continuous Operating Recording Station (CORS) that was available from Jeddah Municipality. In this technique, CORS measures continuously the GPS signals from satellites at a fixed reference base station. Then, we used our rover GPS device to measure the gravity location, and then data from CORS and rover-GPS are integrated as part of a post- processing technique. Once gravity acquisition was completed, data reduction using the Geosoft program (Geosoft 2016) was carried out and residual gravity map was constructed as the first micro- gravity map for the KAU’ s campus. Gravity data was ana- lyzed using various geophysical filters. For example, for edge detection, we used horizontal gradient and analytic signal, and for depth estimation, we used Euler deconvolution and 3D inversion technique. The results indicate that the bedrock of * Essam Aboud eaboudishish@kau.edu.sa 1 Geohazards Research Center, King Abdulaziz University, Jeddah, Saudi Arabia 2 National Research Institute of Astronomy and Geophysics (NRIAG), Cairo, Egypt 3 Geology Department, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt Arabian Journal of Geosciences (2018) 11: 691 https://doi.org/10.1007/s12517-018-4029-x