Qal'eh Hasan Ali is part of the Urmiah-Dokhtar volcanic arc,[3] specifically its southeastern segment.[4] This volcanic arc extends along the Zagros mountain range and has been interpreted as being caused by subduction of the Neotethys, starting during the Triassic. Volcanism reached a peak during the Eocene. The volcanic succession of the arc reaches thicknesses of 4 kilometres (2.5 mi) in some places and is dominated by calc-alkaline rocks.[5] Another volcanic arc in Iran is found in the Makran area and is formed by the Bazman, Taftan and Koh-i-Sultan volcanoes, the second of which lies in Pakistan.