is a

volcanic A volcano is a rupture 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 found where tectonic plates a ...

Japanese island in the

Philippine Sea The Philippine Sea is a marginal sea of the Western Pacific Ocean east of the Philippine archipelago (hence the name), the largest in the world, occupying an estimated surface area of . The Philippine Sea Plate forms the floor of the sea. Its ...

. Nussbaum, Louis-Frédéric. (2005)
"''Izu Shotō'',"
''Japan Encyclopedia,'' p. 412. The island is administered by

Tōkyō Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...

and is located approximately northwest of the

Miyake-jima is an inhabited volcanic island in the Izu archipelago in the Philippine Sea approximately southeast of Tokyo, Japan. As with the other islands in the Izu Island group, Miyake-jima forms part of the Fuji-Hakone-Izu National Park. Etymology ...

and southwest of the Nii-jima. It is one of the Izu Seven Islands group of the seven northern islands of the Izu archipelago. Kōzushima is administratively part of Kōzushima Village under Ōshima Subprefecture of Tokyo Metropolis. , the island's population was 1,952. Kōzushima is also within the boundaries of the

Fuji-Hakone-Izu National Park is a national park in Yamanashi, Shizuoka, and Kanagawa Prefectures, and western Tokyo Metropolis, Japan. It consists of Mount Fuji, Fuji Five Lakes, Hakone, the Izu Peninsula, and the Izu Islands. Fuji-Hakone-Izu National Park covers . Rather ...

Geology

Kōzu-shima is a compound volcanic island 6 km in length with a maximum width of 4 km. The island is formed from a cluster of eighteen

lava dome In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on ...

s, with

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...

and pyroclastic ash deposits. The highest of these lava domes, , has a height of , and was last active in 838 AD per the ancient Japanese history

Shoku Nihon Kōki is an officially commissioned Japanese history text. Completed in 869, it is the fourth volume in the Six National Histories. It covers the years 833–850. Background Following the earlier national history ''Nihon Kōki'' (840), in 855 Emperor ...

. Compared with most of the other islands in the Izu archipelago, Kōzu-shima is relatively flat, with small eroded hills, and lacks the high coastal cliffs found on the other islands.

Earthquake swarms In seismology, an earthquake swarm is a sequence of seismic events occurring in a local area within a relatively short period. The time span used to define a swarm varies, but may be days, months, or years. Such an energy release is different f ...

have occurred at Kōzu-shima during the 20th century.

Climate

Important Bird Area

The island has been recognised as an

Important Bird Area An Important Bird and Biodiversity Area (IBA) is an area identified using an internationally agreed set of criteria as being globally important for the conservation of bird populations. IBA was developed and sites are identified by BirdLife Int ...

(IBA) by

BirdLife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding ...

because it supports populations of

Japanese wood pigeon The Japanese wood pigeon (''Columba janthina'') is a species of columbid bird. It is found in East Asia along shorelines of the Pacific's Korea Strait, Philippine Sea and East China Sea. They are believed to be the largest representative of t ...

Tristram's storm petrel Tristram's storm petrel or ''akihikeehiale'' (''Hydrobates tristrami'') is a species of seabird in the storm petrel family Hydrobatidae. The species' common and scientific name is derived from the English clergyman Henry Baker Tristram; the specie ...

Japanese murrelet The Japanese murrelet or crested murrelet (''Synthliboramphus wumizusume'') is a small seabird in the auk family that occurs along the remote rocky coasts and in the offshore waters of Japan, and may also be found after the breeding season as far ...

Ijima's leaf-warbler Ijima's leaf warbler (''Phylloscopus ijimae'') (also known as Izu leaf warbler, Ijima's willow warbler or Ijima's warbler) is a species of Old World warbler in the family Phylloscopidae. The species is native to Japan, where it has been designate ...

Pleske's grasshopper warbler Styan's grasshopper warbler (''Helopsaltes pleskei''), also known as Pleske's grasshopper warbler and Taczanowski's warbler, is a species of Old World warbler in the family Locustellidae. It breeds in eastern Siberia to Korea, Kyushu and Izu Isl ...

s and

Izu thrush The Izu thrush or Izu Islands thrush (''Turdus celaenops'') is a bird of the thrush family native to Japan. Behavior Feeding Izu thrushes eat small animals, such as earthworms and insects, and fruits, like cherries or mullberries. Breeding Th ...

es.

History

Kōzu-shima has been inhabited since at least the

Japanese Paleolithic The is the period of human inhabitation in Japan predating the development of pottery, generally before 10,000 BC. The starting dates commonly given to this period are from around 40,000 BC; although any date of human presence before 35,000 BC ...

era, and archaeologists have found

Jōmon period The is the time in Japanese history, traditionally dated between 6,000–300 BCE, during which Japan was inhabited by a diverse hunter-gatherer and early agriculturalist population united through a common Jōmon culture, which reached a c ...

stone tools made from

obsidian Obsidian () is a naturally occurring volcanic glass formed when lava extrusive rock, extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Obsidian is produced from felsic lava, rich in the lighter elements s ...

Shizuoka Shizuoka can refer to: * Shizuoka Prefecture, a Japanese prefecture * Shizuoka (city), the capital city of Shizuoka Prefecture * Shizuoka Airport * Shizuoka Domain, the name from 1868 to 1871 for Sunpu Domain, a predecessor of Shizuoka Prefecture ...

and

Yamanashi Prefecture is a prefecture of Japan located in the Chūbu region of Honshu. Yamanashi Prefecture has a population of 817,192 (1 January 2019) and has a geographic area of 4,465 km2 (1,724 sq mi). Yamanashi Prefecture borders Saitama Prefecture to the no ...

s. Under the

Ritsuryō , , is the historical law system based on the philosophies of Confucianism and Chinese Legalism in Japan. The political system in accord to Ritsuryō is called "Ritsuryō-sei" (律令制). ''Kyaku'' (格) are amendments of Ritsuryō, ''Shiki'' (� ...

system of the early

Nara period The of the history of Japan covers the years from CE 710 to 794. Empress Genmei established the capital of Heijō-kyō (present-day Nara). Except for a five-year period (740–745), when the capital was briefly moved again, it remained the cap ...

, the island was part of

Suruga Province was an old province in the area that is today the central part of Shizuoka Prefecture. Suruga bordered on Izu, Kai, Sagami, Shinano, and Tōtōmi provinces; and was bordered by the Pacific Ocean through Suruga Bay to the south. Its abbrevia ...

. It was transferred to

Izu Province was a province of Japan in the area of Shizuoka Prefecture. Nussbaum, Louis-Frédéric. (2005). "''Izu''" in . Izu bordered on Sagami and Suruga Provinces. Its abbreviated form name was . The mainland portion of Izu Province, comprising the ...

when Izu separated from Suruga in 680 AD. During the

Heian period The is the last division of classical Japanese history, running from 794 to 1185. It followed the Nara period, beginning when the 50th emperor, Emperor Kanmu, moved the capital of Japan to Heian-kyō (modern Kyoto). means "peace" in Japanese. ...

, obsidian was the primary export from the island.

Notes

References

* ''Teikoku's Complete Atlas of Japan'', Teikoku-Shoin., Ltd. Tokyo 1990,

External links

Kozushima Village Official Website

- Japan Meteorological Agency * - Japan Meteorological Agency

- Geological Survey of Japan * {{DEFAULTSORT:Kozushima Izu Islands Active volcanoes Islands of Tokyo Important Bird Areas of the Nanpo Islands Seabird colonies VEI-4 volcanoes