Hundreds of small earthquakes have shaken the earth around the Sabancaya volcano in southern Peru over just a few days and the rumbling, along with plumes of smoke spewing up to 100 metres high, have put officials on alert to evacuate the area.
Peru's geological agency Ingemmet recorded 536 quakes, about 20 an hour, on February 22 and 23 and periodic movement is ongoing.
Thousands of people live in the valleys surrounding the volcano.
Some have already started to leave the region because the unusual seismic activity has damaged their homes.
About 80 homes were damaged by one temblor on February 22, Peru's national defence office said.
The 6,000-metre volcano Sabancaya, which means "tongue of fire" in Quechua, has not had a significant eruption in nearly a decade.
It sits atop the South America tectonic plate, which forces magma to the surface when it clashes with the neighboring Nazca plate.
Ingemmet said the volcano has been releasing huge smoke trails intermittently since January 15 and current seismic activity is similar to that which accompanied an eruption in 1986.
Sabancaya, active historically, was dormant for 200 years before erupting into activity several times in the 1980s and 1990s. No casualties were reported at that and the volcano has only experienced small eruptions since.
Southern Peru is the home to more than a dozen volcanoes.
Sabancaya is about 100 kilometres from the city of Arequipa, one of Peru's three largest cities, which was recently hit by heavy rains and flooding.
About 1.2 million people live in that city.