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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 27.881°N
  • 128.223°E

  • 212 m
    695 ft

  • 282020
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports for Io-Torishima.

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

The Global Volcanism Program has no Bulletin Reports available for Io-Torishima.

Basic Data

Volcano Number

Last Known Eruption



1968 CE

212 m / 695 ft


Volcano Types


Rock Types

Andesite / Basaltic Andesite

Tectonic Setting

Subduction zone
Oceanic crust (< 15 km)


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

Geological Summary

The 1 x 2.7 km island of Io-Torishima, located north of the largest island of the Ryukyus, Okinawa, is composed of two andesitic volcanoes. Torishima (Bird Island) is a common name for offshore islands in Japan. Kusuku lava dome occupies the center of the inner of two sommas on the SE-most volcano. The summit crater of the NW-most volcano, Iodake, contains a small lake, solfataras, and sulfur deposits that were mined in the past. Historical eruptions dating back to 1664 have consisted of mild-to-moderate explosive activity.


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

Hayakawa Y, 1996. (pers. comm.).

Japan Meteorological Agency, 1996. National Catalogue of the Active Volcanoes in Japan (second edition). Tokyo: Japan Meteorological Agency, 502 p (in Japanese).

Japan Meteorological Agency, 1975. National Catalogue of the Active Volcanoes in Japan. Tokyo: Japan Meteorological Agency, 119 p (in Japanese).

Japan Meteorological Agency, 2013. National Catalogue of the Active Volcanoes in Japan (fourth edition, English version). Japan Meteorological Agency.

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,

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,

Eruptive History

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1968 Jul 18 1968 Jul 18 Confirmed 1 Historical Observations
1967 Nov 25 ± 5 days Unknown Confirmed 1 Historical Observations
1959 Jun 8 1959 Jul Confirmed 2 Historical Observations Iwo-dake
1903 Mar 15 ± 5 days 1903 Aug 26 ± 5 days Confirmed 2 Historical Observations
1868 Feb 1868 Apr Confirmed 1 Historical Observations
1855 Mar 1855 May Confirmed 2 Historical Observations
1829 Dec 1 1829 Dec 16 Confirmed 1 Historical Observations
1796 Oct 1796 Nov Confirmed 2 Historical Observations Iwo-dake
1664 Unknown Confirmed   Historical Observations

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.


Okinawa-Tori-shima | Io-Tori-sima | Iwo-Tori-shima | Okinawa Iojima


Feature Name Feature Type Elevation Latitude Longitude
Tuff ring 131 m


Feature Name Feature Type Elevation Latitude Longitude
Dome 212 m 27° 52' 52" N 128° 13' 21" E

Photo Gallery

The island of Tori-shima is seen in an aerial perspective from the SW in this computer-generated graphic image. The 1 x 2.7 km island (also known as Okinawa-Tori-shima), consists of two overlapping volcanoes. Iwo-dake (Sulfur Peak) forms the summit of the NW volcano (left), which contains a small lake, solfataras, and sulfur deposits that were mined in the past. A lava dome occupies the center of the inner of two sommas on the SE-most volcano (right), whose high point, Mae-dake, lies at the SE tip of the island.

Photo courtesy of Bird's-Eye Japan (

Smithsonian Sample Collections Database

There are no samples for Io-Torishima in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

Affiliated Sites

Large Eruptions of Io-Torishima 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).
WOVOdat 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.
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).
MODVOLC - HIGP MODIS Thermal Alert System 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.
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.