(means "big island") is an uninhabited island in the
Sea of Japan
The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it h ...
, to the west from
Matsumae town and therefore the westernmost point of
Hokkaido
is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel.
The la ...
. It is part of the town of Matsumae in
Oshima Subprefecture
is a subprefecture of Hokkaido Prefecture, 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
The subprefecture is located on the Oshima Penins ...
in Hokkaido,
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
. To distinguish Ōshima from other islands with the same name, it is sometimes known as or .
At , Ōshima is the largest uninhabited island under Japanese sovereignty. The island is a double caldera with a
scoria
Scoria is a pyroclastic, highly vesicular, dark-colored volcanic rock that was ejected from a volcano as a molten blob and cooled in the air to form discrete grains or clasts.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, eds. (2005) ''G ...
hill rising in the middle. It is the peak of two overlapping
stratovolcano
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and per ...
es and their associated calderas, Mount Higashi and Mount Nishi.
The highest peak, at ,
is part of a triple volcano. The peak rises close to from the sea floor. The island consists of mafic alkali and non-alkali volcanic rock, less than 18,000 years old.
On the south side of the island at , there is a lighthouse and a heliport operated by
Japan Coast Guard
The is the coast guard of Japan.
The Japan Coast Guard consists of about 13,700 personnel and is responsible for the protection of the coastline of Japan under the oversight of the Ministry of Land, Infrastructure, Transport and Tourism. Th ...
.
Because of volcanic activity and nature conservation, landing on the island requires the approval of the
Agency for Cultural Affairs
The is a special body of the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT). It was set up in 1968 to promote Japanese arts and culture.
The agency's budget for FY 2018 rose to ¥107.7 billion.
Overview
The ag ...
.
History
Because of the island's isolation and volcanic activity there are almost no records of its past left behind. had a major eruption on 27 August 1741, which created a large horseshoe-shaped caldera breached to the north and extending from the summit down to the sea floor at the base of the
volcano
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 are ...
. This event produced a mostly submarine debris avalanche that traveled 16 km distance, and triggered a large tsunami. The
tsunami
A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explo ...
devastated the coasts of
Hokkaido
is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel.
The la ...
, western
Honshu
, historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island separ ...
, and as far as
Korea
Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...
, causing nearly 1500 deaths. The 1741 eruption was the largest in historical time at Ōshima and it ended with the construction of a basaltic cinder cone at the head of the breached caldera. No eruptions have occurred since the last eruption in 1790, but seismic unrest under the volcano occurred in 1996.
Flora and fauna
Ōshima is the northern limit of the breeding grounds for the
streaked shearwater
The streaked shearwater (''Calonectris leucomelas'') is a species of seabird. The adult bird averages in length, with a wingspan. Description
The streaked shearwater feeds mainly on fish and squid. It follows fishing boats, attracted to ancho ...
and is part of the Matsumae-Yakoshi Prefectural Natural Park.
Baird's beaked whale
Baird's beaked whale (''Berardius bairdii''), also known as the northern giant bottlenose whale, North Pacific bottlenose whale, giant four-toothed whale, northern four-toothed whale and the North Pacific four-toothed whale, is a species of whale ...
s are targets of commercial whaling in the nearby waters.
[Kasuya T.( jp). 2017]
Small Cetaceans of Japan: Exploitation and Biology
"13.3.2 Regional distribution and population structure". CRC Press
The CRC Press, LLC is an American publishing group that specializes in producing technical books. Many of their books relate to engineering, science and mathematics. Their scope also includes books on business, forensics and information tec ...
. Retrieved on September 25, 2017
See also
*
Desert island
A desert island, deserted island, or uninhabited island, is an island, islet or atoll that is not permanently populated by humans. Uninhabited islands are often depicted in films or stories about shipwrecked people, and are also used as stereot ...
*
List of islands
This is a list of the lists of islands in the world grouped by country, by continent, by body of water
A body of water or waterbody (often spelled water body) is any significant accumulation of water on the surface of Earth or another plane ...
*
List of volcanoes in Japan
This is a list of active and extinct volcanoes in Japan. An Orange background indicates a volcano considered active by the Japan Meteorological Agency.
Hokkaido
Honshū
Izu Islands
Ogasawara Archipelago
The Ogasawara Archipelag ...
References
Sources
* Based on the translation of
:ja:渡島大島 on 12 December 2008
{{DEFAULTSORT:Oshima, Hokkaido
Islands of the Sea of Japan
Islands of Hokkaido
Uninhabited islands of Japan
Matsumae, Hokkaido
Stratovolcanoes of Japan
Calderas of Japan