Active tectonics along the Sheladiz seismogenic fault in the Western Zagros fold-thrust belt, Kurdistan, Northern Iraq

This study attempts to present a clear case of seismic activity caused by the Quaternary reactivation of a seismogenic blind basement fault in the Sheladiz area. This area is located within the Western Zagros fold-thrust belt in the Kurdistan region of northern Iraq, near the north-eastern margin of the Arabian plate. Focal mechanisms of largest earthquakes were provided by the Harvard CMT and UK ISC bulletins. The Sheladiz fault is a NE-trending, nearly vertical to steeply dipping, seismically active left-lateral (sinistral) strike-slip blind basement fault that extends for more than 80 km with focal depths of 18-24 km, and passes transversely through major fold structures. This fault probably coincides with the continuation of Late Precambrian Kutchuk-Duhok and Sinjar-Herki transverse basement faults that forms the boundary between the Sinjar-Abdul Aziz and Deir Al Zor-Erbil transversal blocks in the study area. Left-lateral (sinistral) strike-slip movements along this basement fault may be related to the anticlockwise rotation of the Arabian plate with respect to the Eurasian plate. The stress inversion results indicate a predominant of N-S (05 degrees/003 degrees) oriented maximum compressive stress (sigma 1) in the Sheladiz area. This present-day dominant direction supports the active deformation rates along the Arabia-Eurasia collision zone. Earthquakes in Kurdistan are mainly produced by the neotectonic reactivation of many seismically active blind basement faults that locally occur close to the surface as major faults or well-defined structural and topographic lineaments. The findings of the present study may offer more clues to predict where future earthquakes are most likely to occur.

Automated summary

This study presents a clear case of seismic activity caused by the Quaternary reactivation of a seismogenic blind basement fault. The findings suggest that earthquakes in the Sheladiz area are mainly produced by left-lateral strike-slip movements along a seismically active basement fault. The stress inversion results indicate a predominant N-S oriented maximum compressive stress in the area, supporting active deformation rates along the Arabia-Eurasia collision zone.