# GIS-Analysis for Active Tectonics Assessment of Wadi Al-Arish, Egypt
## 2 Study Area
The Sinai sub-late is locked eastward by the sinistral transform Dead Sea fault and its extension in the the Gulf of Aqaba. Recent remarks and evidence from marine geophysical studies identify the Gulf of Suez and its northward extension as the western boundary of the Sinai sub-plate [13; 26; 32]. The motion of this sub-plate is still under debate [13; 14]. Regarding the motion of Sinai relative to the African plate, seismological and GPS studies indicate the dominance of slab-pull motion rather than ridge push forces [14]. Author of [14] indicates that the southern part of the Gulf of Suez is dominant by an extensional regime accompanied by sinistral motion, which is in agreement with the kinematic models of the authors [33; 34; 35]. The splitting of the Sinai sub-plate from the African plate in the Miocene within the Red Sea opening event frameworks, has continued to the present time [36; 37; 38]. The Suez rift was opened and linked to the Red Sea in the Miocene period [39; 40]. Generally, the latest Miocene provides evidence of reducing tectonic activity along the Suez rift zone [13; 37] concurrent with the Aqaba rift opening [13]. The movement of the Sinai sub-plate relative to the Dead Sea transform fault is estimated to be about 8-9 mm/year [41]. On the other hand, about 1 mm/year was recorded for the extensional motion along the Gulf of Suez rift [37; 42]. The general tectonic styles and trends of faulting provide four main structural frameworks observed in the central and northern Sinai sub-plate, and the Suez and Aqaba gulfs [13]. The Wadi Al-Arish region has different morphological features according to its tectonic and topographic setting, in addition to lithological types [17]. The authors of [16] stated that morphological variations, including differences in elevation and position, are the main cause of variance in temperatures during a given season. Structurally, the Wadi Al-Arish region is highly affected by different structural elements (Figure 4). In the central part, two prominent structural features can be recognized. These are the Minsherah Abu kandu and the Ragabet El-Naam Shear zones cross Wadi Al-Arish providing NE-SW and E-W trends, respectively with a variable displacement up to 2.5 km [43; 44] (Figure 4). This shear zone references the southernmost edge of the Early Mesozoic passive continental margin and the Syrian Arc tectonic front in the north [13; 43]. Fractures/Faults over the study area indicate two main fractures systems with NW-WNW and NE-ENE trends. The authors of [17; 45] state that these fractures and/or faults play an important role in the incision and trending of the majority of drainage systems. For example, over the southern part of Wadi Al-Arish there is compatibility between major trending of the faults/fractures and the main courses of the water systems. In the northern province that comprises Wadi Al-Arish, the deformation style has complex tectonics and large uplifting blocks of Mesozoic anticline folds oriented mostly N65\({}^{\circ}\)-85\({}^{\circ}\)E, as a result of the Syrian Arc System major tectonic [13] (Figure 4) [17]. Based on microetoctonic analysis of the northern province by [46; 47] the Cretaceous/Paleocene shortening structures were initiated from E-W to WNW-ESE by horizontal compression. The Gulf of Suez rift zone has NW-oriented normal faults of varying lengths in the Phanerozoic cover [13]. In addition, the basement rocks are fractured by strike-slip faults with subordinate normal and reverse offsets [13]. Based on a focal mechanism solution and shear analysis, the tectonic style in the Gulf of Aqaba was investigated and modeled, characterizing compressional strain accompanied by sinistral motion faults [34; 48; 49].