Yonaguni

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The factual accuracy of part of this article is disputed.

The dispute is about The topic of Seabed structures.

Please see the relevant discussion on the talk page before making changes.(March 2008)

For the breed of horse, see Yonaguni (horse).

For the administrative division, see Yonaguni, Okinawa.

Yonaguni

Yonaguni (与那国島, Yonaguni-jima^?), or ドゥナンチマ Dunan-chima in the local language, is the name of the westernmost island of Japan, as well as the language spoken there (see Yonaguni language). The native name for the island, Dunan, is cognate with the element Yona- in the Japanese name.

1 Geography
2 History
3 Seabed structures
4 References
5 See also
6 External links

[edit] Geography

Yonaguni lies 125 kilometers (78 mi) from the east coast of Taiwan at the end of the Ryukyu Islands chain. The island has an area of 28.88 km² (11.2 sq mi), a population around 1700, an annual mean air temperature of 23.9°C, and annual precipitation of 3000 mm. Cape Irizaki is the westernmost point in Japan. All islands are under jurisdiction of the town of Yonaguni, Yaeyama Gun, Okinawa and has three towns: Sonai, Kubura and Higawa. It was incorporated under the control of the Ryūkyū royal court in 1610.

[edit] History

Yonaguni was part of the continent until the last ice age. In the 12th century, it was incorporated to the Ryūkyū Kingdom until the 17th century and then incorporated into the Japanese han of Satsuma. By 1879, the island was formally incorporated into Japan. Until the early 20th century, Yonaguni was part of the larger Yaeyama village, which included the neighboring Yaeyama Islands, but then became an independent village in 1948. From 1945 to 1972, it was occupied by the United States and was then returned to Japan to form a part of Okinawa Prefecture.

[edit] Seabed structures

Sunken structures

This island has recently become well known for massive sunken rock and stone formations known as the Yonaguni monument which surround the island. It has been claimed that it is human made. Robert Schoch after diving there suggests that it is most likely a natural formation later modified by human hands^[1].

Divers congregate on the island in winter due to the large population of hammerhead sharks found in nearby waters. It was diving to scout for a good place to observe the sharks which led to the discovery of the "monument", a part of which is two closely spaced pillars which rise to within eight feet of the surface. Study of the curiosity is hampered by a significant ocean current sufficient to exhaust divers if they swim in the opposite direction.

Located at the bottom of the arc of the Ryukyu Islands separating the (marginal) East China Sea from the Pacific Ocean proper, Yonaguni would have been much larger when the ocean was 39 m (100 ft) shallower circa 10,000 BCE as the last Ice Age ended.

The seabed contains what appear to be ruins of a previous glacial age and traces of terrestrial flora, fauna and stalactites that form only on the surface. Their resemblance to structures in the ancient world have led some to theorize they could be the remnents of an ancient civilization. Were they to be human-made they would be among the oldest human made structures at some 10,000 years old.

The fame of Yonaguni island began in the 1980s, when a Japanese marine explorer, Kihachiro Aratake, by chance discovered a set of very singular seemingly architectonic structures. Shortly thereafter, a group of scientists directed by Masaaki Kimura (木村政昭), of the University of the Ryūkyūs, confirmed the existence of the vestiges. They appear, at least superficially, to be comparable to pyramids. Some also speculate that several of the seemingly natural features could in fact be human made, such as the discovery of what some called a "face" on the side of one of the monuments. To date, there is no archaeological evidence to support this theory.

On May 4, 1998, a part of the island was destroyed by a submarine earthquake.

Several analyses indicated that a certain structure, which measured 120 m in length, 40 m wide and 20–25 m high, was 8000 years old.^{[citation needed]} Several noted writers, including John Anthony West and geologist Robert Schoch argue that under inspection, the "ruins" turn out to be largely explicable by ocean erosion and coral reef settlements. Professor Kimura still maintains that the structure is human made.

Most geologists familiar with the area also maintain that the structures are mere geologic processes of natural origin and consistent with other known geological formations.^[2] They point to the fact that local rocks above the surface have right angle cleavages, and that aquatic flora and fauna have simply smoothed out much of the surface of the rocks. Photographs show with a varying degree of clarity parts of the formation with precise geometrical shapes, in varying complexity. Although this may be taken as a strong hint of human presence, many natural formations, such as the Giant's Causeway, or natural staircase structures on Old Rag Mountain^[3], present similar shapes.

The structure called "The Turtle"

At the time that Kimura first suggested it might have been constructed, the affected area of Yonaguni composed a land bridge between the islands of Taiwan, Ryūkyū, and Japan with Asia in the days of the ice age. The level of the sea was lower than at present because of the ice accumulated in the temperate zones. Geologist Teruaki Oshii suggests they have been constructed before the end of the glacial era.

Kimura now argues that Yonaguni is the site of a city at least 5,000 years old which sunk 2,000 years ago, while Robert Schoch says "they're all natural...It's basic geology and classic stratigraphy for sandstones, which tend to break along planes and give you these very straight edges, particularly in an area with lots of faults and tectonic activity."^[4] Kimura claims to have identified at least 15 structures off Yonaguni and Okinawa including a castle, linked by roads and water channels. Kimura obtains his 5,000 years old date for the city from the dates of stalactites in adjacent underwater caves. Kimura also says that he has found images of animals and people, while Schoch considers them natural scratches on the rocks.^[5]