Kozushima
Encyclopedia
is a volcanic
Japanese island in the Philippine Sea
, administered by Tōkyō
and located approximately 30 kilometres (18.6 mi) northwest of the Miyakejima
and 14 kilometres (8.7 mi) southwest of the Niijima. 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. As of 2009, the island's population was 8,363. Kōzushima is also within the boundaries of the Fuji-Hakone-Izu National Park
.
s, with rhyolite
and pyroclastic ash deposits. The highest of these lava domes, , has a height of 571 metres (1,873.4 ft), and was last active in 838 AD per the ancient Japanese history Shoku Nihon Kōki
. Compared with most of the other islands in the Izu archipelago, Kōzushima is relatively flat, with small eroded hills, and lacks the high coastal cliffs found on the other islands. Earthquake swarms have occurred at Kōzushima during the 20th century.
era, and archaeologists have found Jomon period
stone tools made from obsidian
in Shizuoka
and Yamanashi Prefecture
s. Under the Ritsuryō
system of the early Nara period
, the island was part of Suruga Province
. It was transferred to Izu Province
when Izu separated from Suruga in 680 AD. During the Heian period
, obsidian was the primary export from the island.
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
Japanese island in the Philippine Sea
Philippine Sea
The Philippine Sea is a marginal sea east and north of the Philippines occupying an estimated surface area of 2 million mi² on the western part of the North Pacific Ocean...
, administered by Tōkyō
Tokyo
, ; officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family...
and located approximately 30 kilometres (18.6 mi) northwest of the Miyakejima
Miyakejima
is an island in the Izu group, southeast of Honshū, Japan, administered by the Tokyo Metropolitan government, with an area of 55.50 km². The island, 180 km south of Tokyo, is located at 34.5N and 139.34E. As of January 1, 2006, the population of the island is 2884...
and 14 kilometres (8.7 mi) southwest of the Niijima. It is one of the Izu Seven Islands group of the seven northern islands of the Izu archipelago
Izu Islands
The are a group of volcanic islands stretching south and east from the Izu Peninsula of Honshū, Japan. Administratively, they form two towns and six villages; all part of Tokyo. The largest is Izu Ōshima, usually called simply Ōshima....
.
Kōzushima is administratively part of Kōzushima Village
Kōzushima, Tokyo
is a village located in Ōshima Subprefecture, Tokyo, Japan.-Geography:Kōzushima Village covers the islands of Kōzushima, one of the northern islands in the Izu archipelago in the Philippine Sea, south of central Tokyo...
under Ōshima Subprefecture
Oshima Subprefecture
is a subprefecture of Hokkaidō, Japan. As of 2004 it had a population of 456,621 and an area of 3,715.38 km².Hakodate Airport is located in the City of Hakodate.- Geography :-Towns and villages by district:* Futami District** Yakumo* Kameda District...
of Tokyo Metropolis. As of 2009, the island's population was 8,363. Kōzushima is also within the boundaries of the Fuji-Hakone-Izu National Park
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....
.
Geology
Kōzushima 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 domeLava dome
|250px|thumb|right|Image of the [[rhyolitic]] lava dome of [[Chaitén Volcano]] during its 2008–2009 eruption.In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano...
s, with rhyolite
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
and pyroclastic ash deposits. The highest of these lava domes, , has a height of 571 metres (1,873.4 ft), and was last active in 838 AD per the ancient Japanese history Shoku Nihon Kōki
Shoku Nihon Koki
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:...
. Compared with most of the other islands in the Izu archipelago, Kōzushima is relatively flat, with small eroded hills, and lacks the high coastal cliffs found on the other islands. Earthquake swarms have occurred at Kōzushima during the 20th century.
History
Kōzushima has been inhabited since at least the Japanese PaleolithicJapanese Paleolithic
The began around 50,000 to 30,000 BC, when the earliest stone tool implements have been found, and continued to around 14,000 BC, at the end of the last ice age, which corresponds to the beginning of the Mesolithic Jōmon period...
era, and archaeologists have found Jomon period
Jomon period
The is the time in Japanese prehistory from about 14,000 BC to 300 BC.The term jōmon means "cord-patterned" in Japanese. This refers to the pottery style characteristic of the Jōmon culture, and which has markings made using sticks with cords wrapped around them...
stone tools made from obsidian
Obsidian
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth...
in Shizuoka
Shizuoka Prefecture
is a prefecture of Japan located in the Chūbu region on Honshu island. The capital is the city of Shizuoka.- History :Shizuoka prefecture was formed from the former Tōtōmi, Suruga and Izu provinces.The area was the home of the first Tokugawa Shogun...
and Yamanashi Prefecture
Yamanashi Prefecture
is a prefecture of Japan located in the Chūbu region of the island of Honshū. The capital is the city of Kōfu.-Pre-history to the 14th century:People have been living in the Yamanashi area for about 30,000 years...
s. Under the Ritsuryō
Ritsuryo
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"...
system of the early Nara period
Nara period
The of the history of Japan covers the years from AD 710 to 794. Empress Gemmei established the capital of Heijō-kyō . Except for 5 years , when the capital was briefly moved again, it remained the capital of Japanese civilization until Emperor Kammu established a new capital, Nagaoka-kyō, in 784...
, the island was part of Suruga Province
Suruga Province
was an old province in the area that is today the central part of Shizuoka prefecture. It was sometimes called . Suruga bordered on Izu, Kai, Sagami, Shinano, and Tōtōmi provinces; and had access to the Pacific Ocean through Suruga Bay.-History:...
. It was transferred to Izu Province
Izu Province
was a province of Japan in the area of Shizuoka Prefecture. Izu bordered on Sagami and Suruga Provinces. Its abbreviated form name was .The mainland portion of Izu Province, comprising the Izu Peninsula is today the eastern portion of Shizuoka Prefecture and the Izu Islands are now part of...
when Izu separated from Suruga in 680 AD. During the Heian period
Heian period
The is the last division of classical Japanese history, running from 794 to 1185. The period is named after the capital city of Heian-kyō, or modern Kyōto. It is the period in Japanese history when Buddhism, Taoism and other Chinese influences were at their height...
, obsidian was the primary export from the island.