Kilauea

Kilauea
Kilauea in 1983
Type	Shield Volcano
Elevation	4,091 ft
Volcanic Region	Hawaii
Current Status	WATCH
Last Eruption	1983-present

Kīlauea is a shield volcano in the Hawaiian Islands, the most active of the five volcanoes that together form the big island of Hawaii. Located along the southern shore of the island, the volcano, at 300,000 to 600,000 years old, is the second youngest product of the Hawaiian hotspot and the current eruptive center of the Hawaiian–Emperor seamount chain. Because it lacks topographic prominence and its activities historically coincided with those of Mauna Loa, Kīlauea was once thought to be a satellite of its much larger neighbor. Structurally, Kīlauea has a large, fairly recently formed caldera at its summit and two active rift zones, one extending 125 km (78 mi) east and the other 35 km (22 mi) west, as an active fault line of unknown depth moving vertically an average of 2 to 20 mm (0 in 1) per year.

Kīlauea's eruptive history has been a long and active one; its name means "spewing" or "much spreading" in the Hawaiian language, referring to its frequent outpouring of lava. The earliest lavas from the volcano, date back to its submarine preshield stage, and have been recovered by ROVs from its submerged slopes; other flows have been recovered through core samples. Lavas younger than 1,000 years cover 90 percent of the volcano; the oldest exposed lavas date back 2,800 and 2,100 years. The first well-documented Kīlauean eruption occurred in 1823, and since that time the volcano has erupted repeatedly. Most historical eruptions have occurred at the volcano's summit or its southwestern rift zone, and are prolonged and effusive in character; however, the geological record shows that violent explosive eruption|explosive activity predating European contact was extremely common, and should explosive activity start anew the volcano would become much more dangerous to civilians. Kīlauea's current eruption dates back to January 3, 1983, and is by far its longest-lived historical period of activity, as well as one of the longest-lived eruptions in the world; as of January 2011, the eruption has produced 3.5 cubic kilometers of lava and resurfaced 123.2 km2 (48 sq mi) of land.

Kīlauea's high state of activity has a major impact on its mountainside ecology where plant growth is often interrupted by fresh tephra and drifting volcanic sulfur dioxide, producing acid rains particularly in a barren area south of its southwestern rift zone known as the Kaʻū Desert. Nonetheless, wildlife flourishes where left undisturbed elsewhere on the volcano and is highly endemic thanks to Kīlauea's (and the island of Hawaii's) isolation from the nearest landmass. Historically, the five volcanoes on the island were considered sacred by the Hawaiian people, and in Hawaiian mythology Kīlauea's Halemaumau Crater served as the body and home of Pele, goddess of fire, lightning, wind, and volcanoes. William Ellis, a missionary from England, gave the first modern account of Kīlauea and spent two weeks traveling along the volcano; since its foundation by Thomas Jagger in 1912, the Hawaiian Volcano Observatory, located at Kīlauean caldera rim, has served as the principal investigative and scientific body on the volcano and the island in general. In 1916 a bill forming the Hawaii Volcanoes National Park was signed into law by Woodrow Wilson; since then the park has become a World Heritage Site and a major tourist destination, attracting roughly 2.6 million people annually.

Geology

Setting

Like all Hawaiian volcanoes, Kīlauea was created as the Pacific tectonic plate moved over the Hawaiian hotspot in the Earth's underlying mantle. The Hawaii island volcanoes are merely the most recent evidence of this process that, over 70 million years, has created the 6,000 km (3,700 mi)-long Hawaiian–Emperor seamount chain. The prevailing, though not completely settled, view is that the hotspot has been largely stationary within the planet's mantle for much, if not all of the Cenozoic Era. However, while the Hawaiian plume is well-understood and extensively studied, the nature of hotspots themselves remains fairly enigmatic.

Kīlauea is one of five subaerial volcanoes that make up the island of Hawaii, created by the Hawaii hotspot. The oldest volcano on the island, Kohala, is more than a million years old, and Kīlauea, the youngest, is believed to be between 300,000 and 600,000 years of age; Loihi Seamount on the island's flank is even younger, but has yet to breach the surface. Thus it is the Emperor seamount chain second youngest volcano in the Hawaiian – Emperor seamount chain, a chain of shield volcanoes and seamounts extending from Hawaii to the Kuril–Kamchatka Trench in Russia.

Following the pattern of Hawaiian volcanics, Kīlauea would have started out as young submarine volcano, gradually building itself up through subsurface eruptions of alkali basalt before emerging from the sea with a series of explosive eruptions about 50,000 to 100,000 years ago. Since then, the volcano's activity has likely been as it is now, a continual stream of effusive and explosive eruptions of roughly the same pattern as its activity in the last 200 or 300 years.

At most 600,000 years old, Kīlauea is still quite young for a Hawaiian volcano; the oldest volcano on the island, the northwestern Kohala, experienced almost 900,000 years of activity before going extinct. The volcano's foreseeable future activity will likely be much like it has been for the past 50,000 to 100,000 years; Hawaiian and explosive activity will continue to heighten Kīlauea's summit, build up its rift zones, and fill and refill its summit caldera at its current rate for the rest of human history.

Current Volcanic Status

Current Status:

Last Eruption: 1983-present

Current Activity Information: Kilauea continues to erupt at two locations: At the summit, DI inflation started and the lava lake rose a few hours later. At Pu`u `O`o cone, a lava flow probably continues to be active on the east flank. To the southeast of Pu`u `O`o, lava is entering the ocean in multiple areas, both inside and outside the National Park boundary. Gas emissions remain elevated.