The activity of the Khanaqin Fault, east of Iraq and west of Iran, as deduced from Neotectonic evidence and seismicity

The Khanaqin Fault is an N-S extending thrust fault with a shallow dipping angle towards the northeast, with a length of about 125 km. Although the majority of the fault runs in the western side of Iran, it is still called the Khanaqin Fault referring to Khanaqin town in the eastern part of Iraq. In Iraq, the red clastic rocks of the Gercus Formation are thrusted over the carbonate rocks of the Avanah and Pila Spi formations. The Eocene carbonates are thrusted over Oligocene carbonate rocks, which in turn are thrusted over clastic rocks of the Injana Formation; forming a complex of faulted rocks along the border with Iran. The fault planes are not so clear when carbonate rocks are thrusted over carbonate rocks (the second case), whereas in the first and third cases, the fault planes are very clear with a lot of deformations, especially in claystone rocks. On 12 November 2017, an earthquake with a magnitude of 7.3 and a depth of 19 km hit the border area between Iraq and Iran. The epicenter of this earthquake is located 86 km southeast of Sulaymaniyah city and 81 km northeast of Khanaqin town. We have used satellite images and geological maps of different scales to recognize the extension and location of the fault. We also recognized many Neotectonic indications of the region’s tectonic activity. Moreover, the seismic activity recorded for more than a century aligns with the conclusions of this study.