Raoul Island
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Anvil-shaped Raoul Island (Sunday Island), the largest and northernmost of the Kermadec Islands, (located at Template:Coor dm, 900 km SSW of Ata Island of Tonga and 1100 km NNE of New Zealand), has been the source of vigorous eruptive activity during the past several thousand years that was dominated by dacitic explosive eruptions.
The area of the island, including fringing islets and rocks mainly in the Northeast, but also a few smaller ones in the Southeast, is 29.38 km2. The highest elevation is Moumoukai peak, at an elevation of 516 m.
The island is uninhabited, except for the permanently manned Raoul Island Station, a government meteorological and radio station and hostel for Department of Conservation officers and volunteers that has been maintained since 1937 on the northern terraces of the island, about 50 m in elevation above the cliffs of Fleetwood Bluff. Raoul Island Station represents the northernmost outpost of New Zealand.
Satellite Islands and Rocks
The two largest satellite islands are North Island and South Island of Meyer Islands
- Islands and Rocks in the Northeast of Raoul Island
- Fishing Rock
- Egeria Rock
- Meyer Islands
- North Island
- South Island
- Napier
- Nugent
- Herald Islets
- Dayrell Island
- Chanter Islands
- Chanter (North) Island
- South Island
- West Island
- Islands and Rocks in the Southwest of Raoul Island
- Milne Islands
- Dougall Rocks
Two Holocene calderas are found at Raoul. The older caldera cuts the center of Raoul Island is about 2.5 x 3.5 km wide. Denham caldera, formed during a major dacitic explosive eruption about 2200 years ago, truncated the western side of the island and is 6.5 x 4 km wide. Its long axis is parallel to the tectonic fabric of the Havre Trough that lies west of the volcanic arc. Historical eruptions at Raoul during the 19th and 20th centuries have sometimes occurred simultaneously from both calderas, and have consisted of small-to-moderate phreatic eruptions, some of which formed ephemeral islands in Denham caldera. A 240 m high unnamed submarine cone, one of several located along a fissure on the lower NNE flank of Raoul volcano, has also erupted during historical time, and satellitic vents at Raoul are concentrated along two parallel NNE-trending lineaments. The Denham caldera was named for the nearby Denham Bay, itself named for Captain Denham from the H.M.S. Herald, an early explorer of the island.
Three small lakes, Blue Lake (1.17 km², about 40 % overgrown), Green Lake (160,000 m²) and Tui Lake (5,000 m², drinking water quality) are located in the Northern caldera of Raoul Island. The plains surrounding the lakes are called Pumice Flats.
Raoul is part of the Kermadec Islands subtropical moist forests ecoregion, and is largely covered with closed-canopy forest, predominantly of the evergreen tree Metrosideros kermadecensis and the islands' endemic palm, Rhopalostylis cheesemanii. The island has no native land mammals, and was formerly home to vast colonies of seabirds who nested in the forests. Polynesian visitors introduced Polynesian Rats in the 14th century, and Norway Rats, cats, and goats were introduced by European and American visitors in the 19th and 20th centuries. The rats and cats greatly reduced the seabird colonies, which mostly withdrew to offshore islets, and although the goats did not eliminate the tree canopy as they did on other islands, they greatly reduced the understory vegetation.
Goats were removed from the island in 1984; in 2004 rats were successfully eradicated from the island. The island is part of the Kermadec Islands Marine Reserve, New Zealand's largest marine reserve, which was created in 1990.
External link
- Kermadec Islands Marine Reserve (New Zealand Department of Conservation) (http://www.doc.govt.nz/Conservation/Marine-and-Coastal/Marine-Reserves/040~Kermadec/index.asp)
- Highly detailed map (http://ortho.linz.govt.nz/nz_offshore_islands/raoul_high_res.jpg)de:Raoulinsel
