El-Hussaini, A.  <br/><br/>
An application of the second derivative as a tool in tectonic analysis in the qattara depression area, Egypt 

 - 307-313pp.  Illustration 
<br/><br/> The second derivative of gravity anomalies of the Qattara area was analysed and statistically studied for determining the tectonic elements. Zones of zero second derivative were considered as the locations of possible faults. The analysis of a constructed tectonic map portrays the predominance of N45°W, N85°E and N45°E fault trends in addition to less pronounced N15°E and N–S faults. The NW–SE faults are very old and inherited from the basement structures. They acted as first order right-lateral wrench faults during the Alpine tectonism. Second and higher orders of faults, developed as a consequence of these movements, are represented by the N85°E and other less abundant trends. Vertical movements along the existing fault system, in addition to the horizontal displacement, is supported by the analysis of the pronounced anomalies of the second derivative map. The subsurface structural picture of the area is composed of uplifted and downfaulted adjoining blocks. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Tectonic analysis - Qattara area - Egypt<br/>Gravity anomalies - Qattara area - Egypt<br/>Structural geology<br/>Structural analysis<br/>Wrench fault