Abstract
The present work deals with ground magnetic investigations of the Wadi Bani Malik area, 40 km from Jeddah city in Saudi Arabia, to delineate the structural settings and demarcate the possible fractures controlling the contaminated flow in the study area. A magnetic survey has been conducted on the up- and downstream areas of the sewage reservoir and filters have been applied to the measured total field, such as reduction to pole (RTP), normalised source strength, tilt angle, and 3D Euler deconvolution to accomplish the goals. Moreover, the Kaczmarz regularisation algorithm was applied to invert RTP data along two selected profiles to magnetic susceptibility depth section to extract magnetic contacts/faults crossing the Wadi. The Wadi is divided into two areas, upstream (Area 2) and downstream (Area 1). The results show that both areas are composed of complex structural trends. In Area 1, magnetic contacts/faults trend mainly in the NE-SW, NNE-SSW and E-W directions, whereas the major trends in Area 2 are NW-SE. The applied filters revealed that in Area 1 the depth to contacts/ faults ranges from similar to 7 m to similar to 30 m and in Area 2 the depths to contacts/faults are mostly greater than 30 m. Possible subsurface contaminated water flow directions in both areas were deduced from the spatial distribution of these contacts.