干旱区生态环境知识资源中心

Calculated horizontal phase angle and horizontal magnetic-gradient techniques were applied to aeromagnetic survey data to locate the fault zones in the Kab Amiri area of the Central Eastern Desert of Egypt. These 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 level 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 interfaces, 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 vectors gradients maps were computed at the stated interfaces. Moreover, variations 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 to construct two basement tectonic maps.

This study revealed the existence of several sets of fault zones trending in six directions: N-S, NNW-SSE, NW-SE, WNW-ESE, NNE-SSE, and NE-SW. Consequently, two maximum principal stresses could be predicted in the area from these results. These are oriented as follows: ENE (or nearly E-W) and NE stresses.