Imaging the Devene fault system beneath the Iskar floodplain in Bulgaria through shallow electrical resistivity profiling

We studied the Nivyanin fault segment from the Devene fault system in NW Bulgaria, using shallow electrical resistivity profiling. The measured profile was located on the Iskar floodplain near Chomakovtsi village and crossed a lineament that connects the northernmost exposures of Upper Cretaceous limestone and Miocene conglomerate on elevated surfaces in which the Iskar valley was incised. The results suggest that the studied fault segment was a strike-slip fault that was active after the deposition during the Miocene. The fault zone is broad over 100 m and consists of sub-vertical fractures and breccia. Vertical fault displacement did not affect the Quaternary fluvial deposit.