While the 2,965-meter (9,700 foot) volcano straddles the two countries' border, its crater, where most of the activity was under way, leans toward the Argentine side, experts told AFP. Authorities alerted residents in a small nearby community, Biobio, and were monitoring the activity closely, they said.
Mayor Victor Lobos said locals were concerned but said no lava or rocks have been expelled from the crater. "We need to stay calm. There are no evacuations at this time," Lobos added.