Volcan Alcedo is located in the center of Isabela, (also known as Albermarle Island) located between Volcan Darwin to the north and Sierra Negra to the south. The composition of its lavas differs from that of both its neighbors, indicating it has an independent magma plumbing system. It quite symmetrical and rises to an elevation of 1100 m (3650 feet). Relative to its size and height, Alcedo's caldera is large (7 to 8 km in diameter) and shallow (270 m deep). A steam vent, or fumerole, is located on the western side of the caldera. Only one historic eruption is known, a basaltic lava that erupted the southeast flank sometime between 1946 and 1960.