Kilauea Hawaii

Kilauea Hawaii consists of a string of islands, or an archapelago. Kilauea is

located on one of these islands, the central Hawaii island. Kilauea is one of

the world?s most active volcanic craters. Craters are formed either by the

massive collapse of material during volcanic activity, by unusually violent

explosions, or later by erosion during dormancy (Comptons). It is situated on

the southeastern slope of the great volcanic mountain Mauna Loa. Its elevation

is 1111 m (3646 ft.) above sea level. The crater has an area of about 10 sq.

km., which forms a great cavity in the side of the mountain. Volcanic activity

recently has been restricted to an inner crater called Halemaumau. Halemaumau

measures more than 900 m (about 3000 ft.) across and has a depth of about 400 m

(about 1300 ft.). Kilauea has erupted at least once a year since 1952. The

volcano spews an average of 525,000 cubic yards of lava a day and by 1995 had

added about 500 acres of new land to the island (Encarta ?98). By June 1989,

it had destroyed the visitors center at the national park, a stretch of Kalapana

Highway, and more than 65 houses by 1990. Kilauea is located on a hot spot under

the island, and the magma is thought to come from a depth of at least 50 km.

below the surface. A hot spot is an area of volcanic activity near the center of

two lithospeheric plates. Normally, lava streams constantly into the floor of

the crater from subterranean sources which either cools and hardens, or

accumulates until it drains off into other subterranean passages. When greater

volcanic activity occurs, the lava is subjected to sudden changes of level,

where it may escape from vents on the lower slope toward the sea. Kilauea is

classified as a shield volcano. Shield volcanoes have a low, broad profile

created by highly fluid basalt flows that spread over wide areas. The fluid

basalt usually only builds a cone around seven degrees steep. Over thousands of

years though, these cones can reach massive size, which is shown in the Hawaiian

Island volcanoes. The Hawaiian Islands are composed of shield volcanoes, that

have been built up from the sea floor. If measured from sea floor level, some of

the Hawaiian volcanoes are the worlds largest mountains in terms of both height

and volume (Comptons). 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 (Encarta).