Measurement of Magnetic Intensity Using Three Different Sensor Levels and Three Vertical Gradient Determinations to Detect Subsurface Engineering Utilities.

Total Magnetic Intensity (TMI) is measured in southern Baghdad at a site located at the University of Baghdad. These measurements are used to investigate the best sensor levels and the suitable vertical gradients to detect subsurface engineering utilities. The measurement is achieved along three E-W parallel profiles. The length of each profile is 28 meters. The spacing distance between stations for the western half (0-14 meters) of the profile is two meters, while it is one meter for the eastern half (14-28 m). The magnetic measurements were carried out using three sensor levels, these are (2.44 m, 1.83 m, and 1.22 m, to determine the best height suitable for investigating shallow subsurface buried objects. Three vertical magnetic gradient values are determined for each station from the three-level magnetic measurements. This study concludes that the sensor height (1.22m) is better than the others in detecting the shallow sources. The three vertical magnetic gradient profiles coincide in detecting the subsurface sources. The vertical gradient results are better than the relatively high sensor-level measurements. The vertical gradient also seems not to be affected by the spacing distance between stations, as the total magnetic intensity measurements.