Using Electrical Resistivity Survey to Investigate Subsurface Geology in Northwestern Al-Anbar City, Iraq

The stratigraphic sequence was studied in the Rawa region, western Iraq. The Schlumberger array was used for 32 vertical electrical sounding stations (one-dimensional survey) distributed along four electrical traverses across both banks of the Euphrates River. The four apparent resistivity pseudo-sections show that the surface layer ranges from low resistivity values attributed to the unconsolidated Quaternary deposits to high values reflecting the compact soil and rock fragments with exposed hard rock. All the pseudo-sections presented vary in resistivity values from low to high, reflecting the lateral change in lithology due to the presence of subsurface faults. The geoelectrical sections generally characterized seven geoelectrical zones in the first section and five zones in the other sections (2, 3, and 4). Several structural and stratigraphic phenomena have been observed, such as the unconformity contact line between the Anah and Euphrates Formations, five subsurface faults (F1, F2, F3, F4 and F5) and the apparent slope of the interface lines of the geoelectrical zones from North East to South West in sections (1 and 2), then from the South West to the North East in sections (3 and 4), which indicates the presence of the anticlinal fold (Anah anticline) that effects the study area. The objective of the current study is to investigate the subsurface geology of the area using the geoelectrical resistivity method.