Architecture of fault damage zones of normal faults, Gebel Ataqa area, Gulf of Suez rift, Egypt

Abstract

Well-exposed contemporaneous E-W en echelon normal faults and NW-SE oriented normal faults in Gebel Ataqa area (Gulf of Suez) allow comparison of their damage zones. Across all investigated damage zones, the majority of fractures are parallel and sub-parallel to their respective faults irrespective of the regional stress field of the area. Four fracture sets have been recorded across the E-W en echelon normal faults and three fracture sets across the NW-SE normal faults. These fractures form a network by their cross-cutting relationship to generate lithons and rock fragments of various sizes within the damage zones. The area around the fault surface exhibits high level of strain with high fracture density. Fracture spacing increases away from the fault. Fracture density is mirrored across the fault in hanging wall and footwall blocks. The average half width of the studied damage zones ranges between 12 and 14.5 m. Slight change in damage zone width along the fault strike is related to change in throw along the fault.