uplift at Hualca Hualca north of Sabancaya, indicating the role of a shared magmatic system between the two volcanoes. Since then, the volcano has been continuously active with numerous explosions every day, which produce volcanic ash clouds that can rise to elevations of . A persistent gas plume lies above the volcano and repeated emissions of ash have happened, resulting in several alerts for the local population. Lahars have been produced in some occasions, without reports of damage. A lava dome began to grow in 2017 within the crater, with unsteady explosive activity and occasional seismic swarms. In 2020, a second lava dome formed in November but it was destroyed between December and February of that year. Ash emissions and seismic activity continued through 2021 and 2022. Hazards Sabancaya rises above the valleys of the Colca river and of some tributaries of the Siguas river with about 35,000 people living in them. Sabancaya is particularly dangerous for the Colca river valley, north of the volcano; it is a major tourism destination in Peru with about 190,000 visitors per year and with the towns Achoma, Cabanaconde, Chivay, Ichupampa, Lari, Maca, Madrigal, Pinchollo, Yanque and others. About 30,000 people live within from the volcano. The flanks of Sabancaya themselves include roads and a major power line that comes from the and delivers electricity to southern Peru; all of these could be threatened in an eruption. In the case of a major Plinian eruption, at least 60,000 to 70,000 people would be threatened. Rock fall would affect the area close to the summit domes, as would pyroclastic flows; these would be a further hazard to the valleys draining the volcano. The presence of an ice cap is an additional source of danger, as its melting during a volcanic eruption could form hazardous lahars, although the small volume of the ice cap limits their damage potential. The Majes River and Sihuasi River drainages would be threatened by such mudflows in case of an eruption; the former is the site of a major irrigation project. Other dangers from eruptions at Sabancaya are tephra fallout, which can impact the health of people; and lava flows, which however are not much of a threat to humans owing to their slow speed. Volcano monitoring in Peru commenced after the 1986 eruption, with the being created two years later and beginning its work at Sabancaya. The monitoring network around