Morphotectonics inferred from the analysis of topographic lineaments auto-detected from DEMs: Application and validation for the Sinai Peninsula, Egypt

Morphotectonic lineaments observed on the Sinai Peninsula in Egypt were auto-detected from Shuttle Radar Topography Mission 90-m digital elevation model (DEM) and gravity grid data and then analyzed to characterize the tectonic trends that dominated the geologic evolution of this area. The approach employed consists of DEM shading, segment tracing, grouping, statistical analysis of the distribution and orientation of the lineaments, fault plane characterization, and smooth representation techniques. Statistical quantification of counts, mean lengths, densities, and orientations was used to infer the relative severity of the tectonic regimes, to unravel the prominent structural trends, and to demarcate the contribution of various faulting styles that prevailed through time. Restored to the present-day geographic position, prominent N50°–60°W, N20°–40°W, N50°–60°E, and N20°–30°E and less prominent N–S, E–W, and ENE trends were common. The prominence of these trends varied through time. The NW and NE trends showed relatively equal abundances in the Precambrian and the Cambrian whereas the prominence of the NW trends prevailed from the Carboniferous to the Holocene. Lineaments in all formations were near vertical and on average, about 65% showed as strike-slip, 22% as reverse, and 13% as normal faulting styles. Statistics from the detected linear features and the reference geological data reveal the relative severity of five dominant tectonic regimes: Precambrian compression followed by extension at its end, Cretaceous compression, Eocene compression, Miocene extension, and finally Holocene compression. Auto-detected lineaments and the severity of the characterized tectonic periods correspond well with reference data on the geologic structure, geodynamic framework, and the gravity anomaly. Furthermore, the recent significance of the broad structural zones was confirmed by the foci of the earthquake epicenters along and at the intra-plate intersections of the broad lineament zones and at the plate boundaries. The spatial distribution of trends with varying styles of faulting distinguished four main tectonic provinces of marked geodynamics variances.

► Morphotectonic lineaments observed on the Sinai Peninsula are detected and analyzed.
► Structural trends, strength of the tectonic regimes, and faulting styles are unraveled.
► Results corresponded with reference geologic structures and the geodynamic framework.
► Results are validated by the gravity anomaly and the foci of the earthquake epicenters.
► Four main tectonic provinces of marked geodynamics variances are distinguished.