Kilauea

Kilauea, the world's most active volcanic crater, located on central Hawaii Island, Hawaii. It is situated on the southeastern slope of the great volcanic mountain Mauna Loa, at an elevation of 1,247 m (4,090 ft) above sea level, which is more than 3000 m (almost 10,000 ft) below the summit of the mountain. The crater, which forms a great cavity in the side of the mountain, has an area of about 10 sq km (about 4 sq mi); the walls of the crater are from 60 to 210 m (about 200 to 700 ft) high. Except for occasional lava flows across the floor of the crater, volcanic activity in recent times has been restricted to an inner crater called Halemaumau, which measures more than 900 m (about 3000 ft) across and has a depth of about 400 m (about 1300 ft).

Normally, lava streams constantly flow into the floor of the crater from subterranean sources and either cool and harden or accumulate until they drain off into other subterranean passages. During greater volcanic activity, the lava is subject to sudden changes of level, when it may escape from vents on the lower slope toward the sea. In the 20th century, major flows occurred in 1920 and 1921, 1950, 1955, 1959, 1965, and 1969. The current eruption cycle, the longest-running in modern Hawaiian history, began on January 3, 1983. The volcano spews an average of 400,000 cu m (525,000 cu yd) of lava a day and by 1995 had added about 200 hectares (about 500 acres) of new land to the island. By June 1989, it had destroyed the visitors center at the national park, and more than 65 houses by 1990. Since 1911 an observatory has been maintained on the brink of the crater. Kilauea is part of the Hawaii Volcanoes National Park.