Sabancaya is an active stratovolcano in the Andes of southern Peru, about northwest of Arequipa. It is considered part of the Central Volcanic Zone of the Andes, one of the three distinct volcanic belts of the Andes. The Central Volcanic Zone includes a number of volcanoes, some of which like Huaynaputina have had large eruptions and others such as Sabancaya and Ubinas have been active in historical time. Sabancaya forms a volcanic complex together with Hualca Hualca to the north and Ampato to the south and has erupted andesite and dacite. It is covered by a small ice cap which leads to a risk of lahars during eruptions.
Sabancaya has generated numerous long lava flows especially during the early Holocene, while activity in the later Holocene has been more explosive. Historical reports indicate eruptions during the 18th century. The volcano returned to activity in 1986, culminating in a large eruption in 1990. Since then it has been continuously active with the emission of ash and gas.
Name
The name "Sabancaya" is Quechua and means tongue of fire or spitting volcano, likely a reference to the eruptive activity. The name is attested from 1595, implying that volcanic activity was observed since that date.
Geography and geomorphology
Sabancaya lies about northwest of Arequipa. The Rio Colca valley is located north of the Sabancaya-Hualca Hualca-Ampato volcano complex. The principal economic activities in the area are agriculture, animal husbandry, mining and tourism.
Regional
The subduction of the Nazca Plate beneath the South American Plate in the Peru-Chile Trench leads to volcanic activity in the Andes. This volcanic activity presently occurs in three segments, the Northern Volcanic Zone, the Central Volcanic Zone and the Southern Volcanic Zone. There is an additional volcanic belt south of the Southern Volcanic Zone, the Austral Volcanic Zone. Sabancaya is located in the Central Volcanic Zone of the Andes, which extends through southern Peru. Many volcanoes in the Central Volcanic Zone are poorly known, owing to their remote locations and adverse conditions such as high altitude.
Sabancaya is part of a series of volcanoes that line the southwestern coast of Peru at a distance of roughly from the shore. Of these volcanoes, Sabancaya, El Misti, Ubinas, Huaynaputina, Ticsani and Tutupaca have been active during historical time. Further volcanoes in the area with Pliocene-Quaternary activity are Sara Sara, Solimana, Coropuna, Ampato, Chachani, Yucamane, Casiri and Tacora. All these volcanoes are considered part of the Central Volcanic Zone of the Andes, and lie east of the Peru-Chile Trench. Notable among them are Ampato and Coropuna for exceeding a height of , Huaynaputina and El Misti for their large eruptions and Ubinas and Sabancaya for their recent activity.
These volcanoes are found in places where strike-slip faults which delimit the volcanic arc and strike along its length intersect additional faults formed by extensional tectonics. Such faults, mainly normal faults, occur around Sabancaya as well and include the Huambo-Cabanaconde, the Huanca, the Ichupampa, the Pampa Sepina, Sepina, Solarpampa and Trigal faults; the volcanoes Ampato and Sabancaya are aligned on this fault, which may thus be responsible for their existence. These fault systems are still active and experience occasional earthquakes and deformation, and their activity appears to be in part triggered by underground magma movements at Sabancaya.
Local
Sabancaya is high and rises above the surrounding terrain. It forms a group of volcanoes with the northern Hualca Hualca and the southern Ampato in the Cordillera Occidental, which tower above the Colca Canyon in the north and the Siguas Valley in the southwest. Ampato and the more heavily eroded Hualca Hualca are the dominant volcanoes of this group, with Sabancaya forming a northeastward extension of the former away from Ampato's summit. There is evidence of age progression from the oldest, Hualca Hualca, over Ampato, to the youngest volcano, Sabancaya.
Sabancaya consists of two separate centres that are formed by neighbouring domes, Sabancaya I North and Sabancaya II South. The summit crater of the volcano lies between these two domes, with traces of an additional crater just northeast. Despite the presence of an ice cap, lava flows are recognizable in the summit area. They have a total volume of .