The glacier-covered, basaltic-to-dacitic Volcán Macá stratovolcano lies within a caldera and contains a summit lava dome. Five flank cinder cones and lava domes lie along a NE-trending fissure that extends 15 km from the summit SW to Bahía Pérez. The volcano lies along the regional Liquiñe-Ofqui fault zone, and a lava flow from a cinder cone at Bahía Pérez erupted as recently as between 1450 and 1670 CE.