Chilean authorities have issued a top level "red" alert as the Copahue volcano began spewing ash, bringing fears of an imminent eruption.
As yet, no evacuation has been ordered by the National Emergency office, as there are no large towns or cities in the current risk area.
In the area immediately surrounding the volcano, there are around 500 people living in Copahue, and approximately 900 in the town of Caviahue. There are a further 800 people in local indigenous Mapuche communities close to the volcano. A community about 60kms (37 miles) east of Copahue, Alto Biobio, is under heightened alert.
Copahue is a village which is famous for its spa waters.
The Geology and Mining Service said in a statement that, "The intensity of seismic signals suggests the eruption in progress is on the smaller side (but) we are not ruling out the possibility that the activity could turn into a larger-scale eruption."
Ash has been falling on both sides of the border and residents have been told by authorities to await further instructions.
The 2,965-meter high volcano lies on the border with Argentina, and south of the capital Santiago, 280kms southeast (175 miles) of Concepcion, with the crater more on the Argentine side. The BBC is reporting that the ash cloud is now nearly 1.5km (1 mile) high.