Mauna Kea

Mauna Kea
Mauna Kea10.jpg
Mauna Kea with its seasonal snowcap, viewed from Kohala Mountain
Mauna Kea (Hawaii)
Mauna Kea
Mauna Kea
Elevation 4,207.3 metres (13,803 ft) NAVD 88 [1]
Location Hawaii, USA
Range Hawaiian-Emperor seamount chain
Prominence 13,796 feet (4,205 m) Ranked 15th
Coordinates  [1]
Topo map USGS Mauna Kea 19155-G4
Type Shield volcano
Volcanic arc/belt Hawaiian-Emperor seamount chain
Age of rock About 400,000 years
Last eruption About 2460 BC ± 100 years
Listing Ultra
U.S. state high point

Mauna Kea (pronounced /ˌmɔːnə ˈkeɪə/ or /ˌmaʊnə ˈkeɪə/ in English, [ˈmounə ˈkɛjə] in Hawaiian) is a dormant volcano in the U.S. state of Hawaii, one of five volcanoes which together form the island of Hawaii. Pu'u Wekiu, one of numerous cinder cones on the summit plateau, is the highest point in the state.. In the Hawaiian language, mauna kea means "white mountain", a reference to its summit being regularly snow-capped during winter in the Northern Hemisphere.

Mauna Kea can be reached via the Saddle Road.

Contents

Geology

The five volcanoes that form Big Island

The Island of {Hawaii is built from five separate shield volcanoes that erupted somewhat sequentially, one overlapping the other. These are (from oldest to youngest):

Mauna Kea is in the post-shield stage of volcanic evolution, having made the transition from the shield stage about 200,000 to 250,000 years ago. At that time, its appearance was probably quite similar to that of its neighbor Mauna Loa today, a smooth shield volcano with a large summit caldera. Following the transition, eruptions became more explosive in character, resulting in the formation of numerous overlapping cinder cones which eventually filled and completely obscured the caldera. These cinder cones now form the peaks at the summit of Mauna Kea, with several of them exceeding 13,500 feet (4,100 m) in elevation. After several hundred thousand years of slowly building itself up by volcanic activity, the mountain's height is slowly decreasing now as its massive weight depresses the Pacific seafloor beneath it.

The summit of Mauna Kea was entirely covered by a massive ice cap during the Pleistocene ice ages. The summit shows evidence of four periods of glaciation over the last 200,000 years, the last ending about 11,000 years ago, at the end of the most recent ice age. The dense rock at the noted adz quarry near the summit is believed to have been formed when lava erupted under a glacier.

Close to the top is Lake Waiau, the seventh highest lake in the U.S.[2]

Climatic zones and biomes

Mauna Kea view from Kohala

The summit plateau of Mauna Kea is entirely above timberline, with a landscape of mostly bare rock with patches of alpine tundra. Snowfall often occurs at elevations above 11,000 feet (3,400 m) during the period from November through March. During particularly cold and wet winters, which are usually linked to La Niña, a snowpack several feet (1 m) deep may remain in the summit region above 13,000 feet (4,000 m) for weeks or months. This permits skiing and other snowplay activities on the slopes of the cinder cones.

A bit lower is the area where the endemic Mauna Kea Silversword can be found.

Between 5,200 and 8,000 feet (1,600 and 2,400 m) there is a band of ranch land which was formerly koa-mamane forest but has been almost entirely converted to pasture. This area has suffered from heavy infestations of gorse, an invasive species in Hawaii. Most of the north and west slopes are also pasture. The palila, an endangered finch-like honeycreeper, feeds almost exclusively on mamane seeds and lives in mamane-naio forest on the west slope. Large numbers of feral sheep inhabit the upper elevations, and have had a severe impact on the native vegetation.

The windward (eastern) slopes are covered in rainforest between about 1,500 and 5,200 feet (460 and 1,600 m). Lower on the mountain are extensive agricultural lands that formerly included vast areas of sugarcane. With the collapse of the sugar industry in the 1990s, much of this land lies fallow but portions are used for cattle grazing, small-scale farming and the cultivation of eucalyptus for wood pulp.

Astronomy

Main article: Mauna Kea Observatory
Mauna Kea Observatory

The summit of Mauna Kea has been a celestial observatory since ancient times and is considered to be one of the best astronomical sites in the world. For this reason it is home to many of the world's leading astronomical observatories. The summit is above approximately 40% of Earth's atmosphere and 90% of the water vapor, allowing for exceptionally clear images of the night sky. Additionally, the peak is well above the inversion layer, allowing up to 300 clear nights per year. Also, at 20°N latitude, much of both the northern and southern skies are visible. The fact that it is a shield volcano has meant that road transportation to the summit is relatively easy. The low population density of the Island of Hawaii means that there is little light pollution from man-made sources. All of these factors have made Mauna Kea an ideal location for state-of-the-art astronomy.

Construction of telescopes on Mauna Kea has been a source of intense legal and political controversy in recent years. Due to the qualities listed above, it is a highly favored location and the summit area is now home to over a dozen telescopes. Native Hawaiians and environmental groups have protested that construction of additional telescopes would cause considerable environmental damage and further desecrate a site of great cultural importance. According to legend, the summit of Mauna Kea is the home of the snow goddess, Poliahu, and many other deities. It is also an important site for prayer, burials, consecration of children, and traditional celestial observation. In addition, the summit area is home to a unique insect, the wēkiu bug, which feeds on insects blown to the summit by updrafts. The insect itself is a major point of debate.[3] Large mercury spills and sewage dumps have also occurred at the existing telescopes; these are of particular concern because of the unique and otherwise-pristine underground water systems in the area.[4]

Over the past decade, major legal battles have raged through Hawaii's court system over these issues. On January 19, 2007, the Third Circuit Court reaffirmed its decision to halt all further development on Mauna Kea until an appropriate Management Plan that sufficiently addresses the environmental damage and cultural impacts posed by astronomical development has been fully approved.[5]

Despite the courts' rulings against further development, plans for additional telescopes have been moving forward. Several science institutes, in collaboration with the United States Air Force are planning to build Pan-STARRS, a major telescope project.[6] Citing the extinction of the dinosaurs and a recent impact on Jupiter,[7] the telescope should be a protection against an asteroid impact. Opponents, however, believe the application to be military in nature.[6] Also the Thirty Meter Telescope (TMT) project, the single largest telescope ever built on Earth, is currently being proposed by Caltech with funding and technology from Intel Corporation.[8] The telescope's developers propose to give scholarships for native Hawaiians as compensation for some of the cultural and environmental destruction that the project would entail.[9] Hearings for this project were scheduled throughout October 2008.

Ski areas

There are limited ski areas on Mauna Kea, with no ski lifts or services provided.

See also

References

  1. ↑ 1.0 1.1 "Summit USGS 1977". NGS Data Sheet. U.S. National Geodetic Survey. Retrieved on 2008-12-06.
  2. ↑ "The Highest Lake in the United States of America". Retrieved on 2008-10-11.
  3. ↑ "Tiny bug may affect astronomy plans". The Honolulu Advertiser (2003-05-23). Retrieved on 2008-10-07.
  4. ↑ "KAHEA: Mauna Kea". Kahea.org. Retrieved on 2008-10-07.
  5. ↑ "KAHEA: Mauna Kea". Kahea.org. Retrieved on 2008-10-07.
  6. ↑ 6.0 6.1 "KAHEA: Mauna Kea". Kahea.org. Retrieved on 2008-10-07.
  7. ↑ "The Threat to Earth from Asteroids and Comets". Pan-starrs. .University of Hawaii. Retrieved on 2008-10-07.
  8. ↑ Sanoe Kauhane. "Big Island Weekly - Read". Bigislandweekly.com. Retrieved on 2008-10-07.
  9. ↑ "Giant telescope eyes site on Mauna Kea". The Honolulu Advertiser. Retrieved on 2008-10-07.

Bibliography

External links

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