STRUCTURAL INTERPRETATION OF AIRBORNE MAGNETIC SURVEY DATA IN THE KAB-AMIRI AREA, CENTRAL EASTERN DESERT, EGYPT

Calculated horizontal phase angle and horizontal magnetic-gradient tec hniques were applied to aeromagnetic survey data to locate the fault z ones in the Kab Amiri area of the Central Eastern Desert of Egypt. The se zones correlate well with the faults shown on geological maps. Two main average interfaces at 0.4 and 0.8 km below the survey flight leve l were calculated through the computation of the local power spectrum of the aeromagnetic data. Filtering combined with analytical downward continuation of the reduced-to-the-pole (RTP) magnetic map at two inte rfaces, was also conducted to produce four maps: one for the regional and the other for the residual component of the magnetic field at each interface. In addition, the normalized horizontal and the total vecto rs gradients maps were computed at the stated interfaces. Moreover, va riations of the horizontal phase angles were calculated and additional two maps were prepared. The information obtained from the application of the various methods of interpretation techniques were integrated t o construct two basement tectonic maps. This study revealed the existe nce of several sets of fault zones trending in six directions: N-S, NN W-SSE, NW-SE, WNW-ESE, NNE-SSE, and NE-SW. Consequently, two maximum p rincipal stresses could be predicted in the area from these results. T hese are oriented as follows: ENE (or nearly E-W) and NE stresses.