Aso-san (ä`sō-sän), volcanic mountain, central Kyushu, Japan. Aso-san is topped by one of the world's largest calderas (circumference 75 mi/121 km) that contains five volcanic cones. Taka-dake (5,225 ft/1,593 m) is the highest cone; Naka-dake (4,340 ft/1,323 m) is an active volcano. Cable cars carry people over the caldera. Aso-san is part of Aso National Park (282 sq mi/730 sq km; est. 1934), which also includes Kuju-san (5,866 ft/1,788 m), the highest peak of Kyushu.