HALEAKALA

volcanic mountain, eastern Maui Island, Hawaii, U.S., central feature of Haleakala National Park. The mountain has the world's largest dormant volcanic crater, measuring 20 miles (32 km) in circumference. In several places the rim of the crater rises more than 2,500 feet (760 m) above the crater floor. Haleakala was last active in the mid-18th century. The name Haleakala (Hawaiian: House of the Sun) derives from the legend that the demigod Maui imprisoned the sun there in order to lengthen the day. Haleakala's western slopes, which are crossed by intermittent rain-fed streambeds, rise gently to the Haleakala summit (10,023 feet ). The heavily eroded terrain of the mountain's eastern flank has deep valleys and gorges. From the volcano's rim, lava poured down its flanks to the sea, following the paths of the Keanae and Kaupo valleys. The crater floor, covering more than 19 square miles (49 square km), has areas of forest, desert, and meadow and a lake. Its northern and eastern portions are used as grazing lands; its southern and western sections, however, are arid and have varicoloured conical cinder deposits up to 1,000 feet (305 m) high that were formed by secondary eruptions. Trade-wind rain clouds drift in over the volcano's low eastern rim, often accumulating in the crater's centre. This phenomenon leaves the high northern rim, Hanakauhi, above the clouds and can produce the unusual spectre (known as Brocken bow) of an observer's greatly magnified shadow thrown on the bank of clouds. Haleakala National Park was created in 1960. The 28,655-acre (11,597-hectare) park includes the crater, Kipahulu Valley, and the Oheo Pools area on the eastern slope. Feral goats and pigs, petrels, and the rare nene (Hawaiian goose) inhabit the crater. Silverswords, rare yuccalike plants that take as long as 20 years to flower once and then die, grow on the walls within the crater, usually on the barren cinder slopes. Horseback riding and hiking are popular on the 30 miles (50 km) of trails inside the crater. Located on the crater rim is Science City, a research-observatory complex for astrophysical studies operated by the U.S. Department of Defense and the universities of Hawaii and Michigan. The Smithsonian Institution, the Air Force, and the Federal Aviation Agency also have facilities there.