The volcano in southwestern Peru blasted back to life causing about 60 villagers from Querapi, near its base, to be relocated Saturday, Ubinas town mayor Pascual Coaquira said.
"We are readying a shelter for refugees from the blasts," he said on Tuesday.
"The volcano has been emitting a lot of ash all day, the people in the town (of Ubinas) are having some problems breathing, the mayor added. They have been given masks," he said.
Peru's geological and mining agency (Ingemmet) said lava had been building up in recent weeks, and warned locals they should prepare for the possibility of more evacuations.
In the broader Moquegua area plus Arequipa and Tacna, there are about 40 volcanoes, most dormant.
On Earth, volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are not usually created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust in the interiors of plates, e.g., in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism. Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth.