Mount Hasan () is a volcano in Anatolia, Turkey. It has two summits, the high eastern Small Hasan Dagi and the high Big Hasan Dagi, and rises about above the surrounding terrain. It consists of various volcanic deposits, including several calderas, and its activity has been related to the presence of several faults in the area and to regional tectonics. Activity began in the Miocene and continued into the Holocene; a mural found in the archeological site of Çatalhöyük have been controversially interpreted as showing a volcanic eruption or even a primitive map. It was the second mountain from the south in the Byzantine beacon system used to warn the Byzantine capital of Constantinople of incursions during the Arab–Byzantine wars. Etymology The modern name of Mount Hasan is widely accepted to be in dedication to Ebu'l-Gazi (El-Hasan), brother of Ebu'l-Kasım during the reign of the Anatolian Seljuks. It is hypothesized that Mount Hasan’s name was “Argeos” or “Argaios”, but this name belongs to Mount Erciyes. Another hypothesis is that it was simply called Árgos, (Ancient Greek: Ἄργος) as well as Argeiopolis Mons. Mount Hasan was named Athar during the Hittites period. Geography and geomorphology Mount Hasan lies in the Anatolian plateau, between the Taurus Range and the Pontic Mountains, and its and Mount Erciyes's silhouettes dominate the landscape and rise high above the surrounding terrain. The city of Aksaray lies northwest from Mount Hasan, while the settlements of Helvadere, Uluören, Dikmen and Taşpınar lie clockwise from north to northwest around the volcano. In addition, there are seasonal settlements on the volcano which are associated with summer pastures. Mount Hasan is part of a larger volcanic province in Central Anatolia known as the Central Anatolian or Cappadocian Volcanic Province., which includes ignimbrites, monogenetic volcanic fields and stratovolcanoes such as Mount Erciyes, Mount Hasan, Karacadağ and Melendiz Dağ with an area of about -. Volcanism took place during the Plio-Pleistocene and into the Quaternary. The volcano has two summits, the high eastern Small Hasan Dagi/ and the high Big Hasan Dagi/; both are located within a caldera and consist of lava domes and lava flows. Big Hasan Dagi has two nested craters with an wide and high inner cone that is the source of a lava flow. Fossil rock glaciers are found on the volcano. The volcano as a whole rises almost around the surrounding terrain and covers an area of with