How long is the Central Volcanic Zone of the Andes?
Andean Volcanic Belt
The South Volcanic Zone (SVZ) extends roughly from Central Chile's Andes at the latitude of Santiago, at ca. 33°S, to Cerro Arenales in Aysén Region at ca. 46°S, a distance of well over 870 mi (1,400 km). The arc has formed due to subduction of the Nazca Plate under the South American Plate along the Peru–Chile Trench. The northern boundary of the SVZ is marked by the flat-slab subduction of the Juan Fernández Ridge, which is believed to have produced a volcanic gap called the "Pampean flat-slab segment" in the Norte Chico region since the late Miocene. The southern end of the SVZ is marked by the Chile Triple Junction where the Chile Rise subducts under South America at the Taitao Peninsula giving origin to the "Patagonian Volcanic Gap". Further south lies the Austral Volcanic Zone.
Macusani (volcano)
Volcanism and tectonism in the Central Andes has been ongoing since the late Oligocene. Volcanism has been occurring in two broad regions, the principal volcanic arc and a secondary volcanic arc in the Cordillera Oriental whose origin is less clear. In that area, the Brazilian Shield subducts beneath the Andean orogen. The origin of the Macusani volcanics has been variously attributed to frictional heating of the subducting Brazilian shield, the subduction itself or a hotspot.