Argentina's seismic and volcanic activity is concentrated along its western edge, where the Nazca Plate subducts beneath the South American Plate to build the Andes. This ongoing collision fuels a chain of volcanoes and generates powerful earthquakes, especially in the provinces of Mendoza, San Juan and Salta near the Chilean border.
The country shares many Andean volcanoes with Chile, including Tupungato and the towering Ojos del Salado region, while Copahue in Neuquén remains one of its most restless. Argentina also suffered one of its deadliest quakes in San Juan in 1944, a magnitude 7.0 event that destroyed much of the city and reshaped national building codes.