Global Volcanism Program

Most Recent Bulletin Report: March 1996 (BGVN 21:03) Cite this Report

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.

The Global Volcanism Program has no Weekly Reports available for Oshima-Oshima.

Bulletin Reports - Index

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

Information is preliminary and subject to change. All times are local (unless otherwise noted)

March 1996 (BGVN 21:03) Cite this Report

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.

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.

Synonyms

O-sima | Osima-Osima

Cones

Feature Name

Feature Type

Elevation

Latitude

Longitude

Higashi-yama

Stratovolcano

737 m

Kanpo-dake

Pyroclastic cone

680 m

Nishi-yama

Stratovolcano

722 m

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude

285010

1790 CE

732 m / 2,402 ft

41.51°N
139.367°E

Morphology

Volcano Landform
Composite

Volcano Types
Stratovolcano
Caldera(s)
Pyroclastic cone

Rock Types

Major
Basalt / Picro-Basalt
Andesite / Basaltic Andesite

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km

6
6
6
88,023

Geological Summary

Oshima-Oshima, a 10 km² island about 105 km W offshore from 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 CE, producing a mostly submarine debris avalanche that traveled 16 km and leaving a scarp open to the north. A tsunami associated with the collapse swept the coasts of Hokkaido, western Honshu, and Korea, and caused nearly 1,500 fatalities. The 1741 eruption concluded with the construction of a basaltic pyroclastic cone at the head of the amphitheater. No eruptions have occurred since the late-18th century.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

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, https://gbank.gsj.jp/volcano/index_e.htm.

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. Geophysical Research Letters, 28: 427-430.

Eruptive History

There is data available for 5 confirmed Holocene eruptive periods.

1790 Jan (?) Confirmed Eruption VEI: 2

Episode 1 | Eruption

Nishi-yama

1790 Jan (?) - Unknown

Evidence from Observations: Reported

List of 2 Events for Episode 1 at Nishi-yama

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Explosion	weak or small
	1790 Jan (?)	- - - -	VEI (Explosivity Index)

[ 1786 ] Uncertain Eruption

Episode 1 | Eruption

Nishi-yama

1786 - Unknown

Evidence from Unknown

List of 2 Events for Episode 1 at Nishi-yama

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Volcanic "smoke"
	1786	- - - -	VEI (Explosivity Index)

1759 Aug 19 Confirmed Eruption VEI: 2

Episode 1 | Eruption

Nishi-yama

1759 Aug 19 - Unknown

Evidence from Observations: Reported

List of 3 Events for Episode 1 at Nishi-yama

Start Date	End Date	Event Type	Event Remarks
- - - -	- - - -	Explosion	weak or small
- - - -	- - - -	Ash
1759 Aug 19	- - - -	VEI (Explosivity Index)

1741 Aug 18 (?) - 1742 May Confirmed Eruption VEI: 4

Episode 1 | Eruption

Nishi-yama

1741 Aug 18 (?) - 1742 May

Evidence from Observations: Reported

List of 11 Events for Episode 1 at Nishi-yama

Start Date	End Date	Event Type	Event Remarks
- - - -	- - - -	Explosion	violent, strong, or large
- - - -	- - - -	Lava flow
- - - -	- - - -	Cinder Cone
- - - -	- - - -	Avalanche
- - - -	- - - -	Ash
- - - -	- - - -	Tsunami
- - - -	- - - -	Edifice Destroyed	Collapse/avalanche
- - - -	- - - -	Property Damage
1741 Aug 18 (?)	- - - -	VEI (Explosivity Index)
1741 Aug 23	- - - -	Fatalities
1741 Aug 29	- - - -	VEI (Explosivity Index)

0250 ± 150 years Confirmed Eruption

Episode 1 | Eruption

Nishi-yama

0250 ± 150 years - Unknown

Evidence from Isotopic: 14C (uncalibrated)

List of 2 Events for Episode 1 at Nishi-yama

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Explosion
	- - - -	- - - -	Ash

0800 BCE ± 100 years Confirmed Eruption

Episode 1 | Eruption

Nishi-yama

0800 BCE ± 100 years - Unknown

Evidence from Isotopic: 14C (uncalibrated)

List of 2 Events for Episode 1 at Nishi-yama

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Explosion
	- - - -	- - - -	Ash

Deformation History

There is no Deformation History data available for Oshima-Oshima.

Emission History

There is no Emissions History data available for Oshima-Oshima.

Photo Gallery

Oshima-Oshima volcano is seen here from the N with the Kanpodake cone (back-center) that formed during the 1741 eruption. Major edifice collapse that year produced a large scarp open to the north, with the walls visible at the sides of the image. The 4-km-wide island is 55 km W of the SW tip of Hokkaido, and is the emergent summit of two coalescing volcanoes: Higashiyama at the eastern end of the island, and Nishiyama at the western 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/).

GVP Map Holdings

Maps are not currently available due to technical issues.

Smithsonian Sample Collections Database

The following 2 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number	Sample Description	Lava Source	Collection Date
NMNH 112974	Hornblende Basalt	--	--
NMNH 112975	Olivine Basalt	--	--

External Sites

Copernicus Browser

The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions.

MIROVA

Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.

MODVOLC Thermal Alerts

Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.

WOVOdat
   Single Volcano View
   Temporal Evolution of Unrest
   Side by Side Volcanoes

WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.

GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments.

Volcanic Hazard Maps

The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter.

IRIS seismic stations/networks

Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Oshima-Oshima. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice.

UNAVCO GPS/GNSS stations

Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Oshima-Oshima. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player.

DECADE Data

The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO₂ to the atmosphere, but installing CO₂ monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere.

Large Eruptions of Oshima-Oshima

Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

EarthChem

EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).