or Iwo Tori-shima, also called Okinawa Torishima (沖縄鳥島), is a

volcanic A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often fo ...

island part of the Ryūkyū Island chain with the only active volcano in

Okinawa Prefecture is the southernmost and westernmost prefecture of Japan. It consists of three main island groups—the Okinawa Islands, the Sakishima Islands, and the Daitō Islands—spread across a maritime zone approximately 1,000 kilometers east to west an ...

Geography

Iotourishima is located 65 km west of

Tokunoshima , also known in English as is an island in the Amami archipelago of the southern Satsunan Islands of Kagoshima Prefecture, Japan. The island, in area, has a population of approximately 27,000. The island is divided into three administrative t ...

Island. On exceptionally clear days, Iōtorishima can be seen from the west coast of Tokunoshima. The 2.50 km² large island consists of two interconnected volcanoes made from

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

. The southern Gusuku kazan (グスク火山, "Castle Volcano") is a lava dome located in the center of the two summits. The northern Iōdake-kazan (硫黄岳火山, "Sulfur Peak Volcano") is a

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

whose crater consists of a small lake of

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

. It is still active, although none of the recent outbreaks had explosive character. The highest point of the island is at 212 m, which belongs to Iōdake-kazan; the highest of the Gusuku kazan is the Maedake (前嶽) at 189.3 m.

History

Sulfur was mined by the inhabitants for centuries within the

Kingdom of Ryukyu The Ryukyu Kingdom was a kingdom in the Ryukyu Islands from 1429 to 1879. It was ruled as a tributary state of imperial Ming China by the Ryukyuan monarchy, who unified Okinawa Island to end the Sanzan period, and extended the kingdom to t ...

, and it was used as tribute to the Chinese Empire. The first recorded eruption was in 1664, when a woman died from a

landslide Landslides, also known as landslips, rockslips or rockslides, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, mudflows, shallow or deep-seated slope failures and debris flows. Landslides ...

. In a series of eruptions and earthquakes from March to August 1903, all residents were temporarily moved 220 km to

Kume Island is an island, part of the Okinawa Islands and administratively part of the town of Kumejima, Okinawa Prefecture, Japan. It has an area of . The island had a population of 8,713 (2010). Kume Island is a volcanic island. Its principal economic a ...

, but were permanently relocated by June 1958; the final settlement had 86 inhabitants. Since then, the island has been uninhabited. In July 1968 there was another eruption. Administratively, the island belonged to Gushikawa on Kume-jima, but merged in 2002 with Nakazato to the city

Kumejima is a town located in Shimajiri District, Okinawa Prefecture, Japan. The town consists of the islands of Kume, Ōjima, Ōhajima, Torishima, and Iōtorishima. Among the islands, only Kumejima and Ōjima are populated. Kumejima is located appr ...

External links

Commons: Io-Torishima - Collection of pictures, videos and audio files relating to the island.

References

{{coord, 27.8711, 128.2269, format=dms, type:isle_region:JP, display=title Islands of Okinawa Prefecture Volcanoes of Japan Kumejima, Okinawa

Geography

History

See also

External links

References