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The Global Volcanism Program has no activity reports for Oshima-Oshima.
The Global Volcanism Program has no Weekly Reports available for Oshima-Oshima.
Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.
03/1996 (BGVN 21:03) Earthquakes and tremor detected
03/1996 (BGVN 21:03) Earthquakes and tremor detected
Volcanic earthquakes and tremors were detected near the end of March by instruments maintained by Hokkaido University.
This small island 55 km W of Hokkaido in the Japan Sea consists of two coalescing volcanoes. An eruption in August 1741 produced heavy ashfall on the Hokkaido mainland. A violent explosion and landsliding from the Nishi-yama cone accompanied a large tectonic earthquake and a major tsunami that killed 1,475 people, most on the W coast of the Oshima Peninsula. Subsequent eruptions through early 1742 produced a new central cone and lava flows. Minor explosive activity was documented in 1759, 1786, and 1790.
Information Contacts: Volcanological Division, Seismological and Volcanological Department, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100 Japan.
Oshima-Oshima, a small, 4-km-wide Japan Sea island 55 km west of the SW tip of Hokkaido, is the emergent summit of two coalescing basaltic-to-andesitic stratovolcanoes. Higashiyama, at the east end of the island, is cut by a 2-km-wide caldera covered on its west side by Nishiyama volcano. The western cone failed during an eruption in 1741, creating a large horseshoe-shaped caldera breached to the north that extends from the summit down to the sea floor at the base of the volcano and producing a mostly submarine debris avalanche that traveled 16 km. A tsunami associated with the collapse swept the coasts of Hokkaido, western Honshu, and Korea, and caused nearly 1500 fatalities. The 1741 eruption, the largest in historical time at Oshima-Oshima, concluded with the construction of a basaltic pyroclastic cone at the head of the breached caldera. No eruptions have occurred since the late-18th century.
Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).
|Start Date||Stop Date||Eruption Certainty||VEI||Evidence||Activity Area or Unit|
|1790 Jan (?)||Unknown||Confirmed||2||Historical Observations||Nishi-yama|
|[ 1786 ]||[ Unknown ]||Uncertain||2||Nishi-yama|
|1759 Aug 19||Unknown||Confirmed||2||Historical Observations||Nishi-yama|
|1741 Aug 18 (?)||1742 May||Confirmed||4||Historical Observations||Nishi-yama|
|0250 ± 150 years||Unknown||Confirmed||Radiocarbon (uncorrected)||Nishi-yama|
|0800 BCE ± 100 years||Unknown||Confirmed||Radiocarbon (uncorrected)||Nishi-yama|
This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.
|O-sima | Osima-Osima|
|Feature Name||Feature Type||Elevation||Latitude||Longitude|
|Kanpo-dake||Cinder cone||680 m|
|Oshima-Oshima volcano is seen here from the north with Kanpo-dake, the pyroclastic cone formed following the 1741 eruption on the center horizon. Major edifice collapse in that year produced a large horseshoe-shaped caldera open to the north, whose walls are visible at the sides of the image. Oshima-Oshima, a small, 4-km-wide Japan Sea island 55 km west of the SW tip of Hokkaido, is the emergent summit of two coalescing stratovolcanoes, Higashi-yama, at the east end of the island, and Nishi-yama at the west end.
Copyrighted photo by Tomoyo Hayakawa (Japanese Quaternary Volcanoes database, RIODB, http://riodb02.ibase.aist.go.jp/strata/VOL_JP/EN/index.htm and Geol Surv Japan, AIST, http://www.gsj.jp/).
The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.
Fujitani T, Masuda A, 1982. Wholly compatible and complementary patterns of rare-earth elements in Quaternary volcanic rocks from Oshima-Oshima and Oshima-Kojima isles, Japan. Geochem J, 16: 23-31.
Japan Meteorological Agency, 1996. National Catalogue of the Active Volcanoes in Japan (second edition). Tokyo: Japan Meteorological Agency, 502 p (in Japanese).
Katsui Y, Yamamoto M, 1981. The 1741-1742 activity of Oshima-Oshima volcano, north Japan. Hokkaido Univ Fac Sci J, 19: 527-536.
Kudo T, Hoshizumi H, 2006-. Catalog of eruptive events within the last 10,000 years in Japan, database of Japanese active volcanoes. Geol Surv Japan, AIST, http://riodb02.ibase.aist.go.jp/db099/eruption/index.html.
Kuno H, 1962. Japan, Taiwan and Marianas. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 11: 1-332.
Nakano S, Yamamoto T, Iwaya T, Itoh J, Takada A, 2001-. Quaternary Volcanoes of Japan. Geol Surv Japan, AIST, http://www.aist.go.jp/RIODB/strata/VOL_JP/.
Satake K, Kato Y, 2001. The 1741 Oshima-Oshima eruption: extent and volume of submarine debris avalanche. Geophys Res Lett: 28: 427-430.