Izu-Torishima

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 30.484°N
  • 140.303°E

  • 394 m
    1292 ft

  • 284090
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

3 July-9 July 2013

According to the Tokyo VAAC a pilot observed an ash plume from Tori-shima drifting at an altitude of 2.1 km (7,000 ft) a.s.l. on 6 July.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)

Index of Weekly Reports


2013: July
2002: August

Weekly Reports


3 July-9 July 2013

According to the Tokyo VAAC a pilot observed an ash plume from Tori-shima drifting at an altitude of 2.1 km (7,000 ft) a.s.l. on 6 July.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)


21 August-27 August 2002

An eruption began at Tori-shima on 11 August and an aerial inspection by the Japan Coast Guard on 21 August revealed that "smoke" was no longer rising from the volcano as it had been on the 14th. Weak steaming was visible in the southern part of the crater. In addition, the sea surface around the island was faintly discolored.

Source: Japan Meteorological Agency (JMA) via the Volcano Research Center


14 August-20 August 2002

The eruption that began at Tori-shima on 11 August continued until at least noon on the 14th. Eruption clouds reached ~1.2 km a.s.l. on the 13th and ~1 km a.s.l. on the 14th. During observations on the 14th, scientists found smoke was being emitted from three areas on the western inner wall of the summit crater. They also found that the crater seemed to have widened during the eruption and the sea surface was no longer discolored.

Source: Japan Meteorological Agency (JMA) via the Volcano Research Center


7 August-13 August 2002

On 11 August around 1530 a ship sailing near Tori-shima reported to the Japan Coast Guard that they observed white smoke rising from the summit of the volcano. JMA reported that an aerial inspection the following day during 1145-1245 revealed an ash-laden plume rising from the SW crater wall of the summit crater (Iwoyama) and white plumes emanating from the S to SE portion of the crater wall. Vigorous ash plumes rose 200-300 m above the crater every few minutes, drifted W, and ultimately reached a height of 1 km a.s.l. The summit area and the middle slope NNW of the summit were covered with ash-fall deposits. Discolored sea water extended 20 km W of the island. Tori-shima is not inhabited by humans, but an endangered albatross species lives there.

Sources: Japan Meteorological Agency (JMA) via the Volcano Research Center; Associated Press; Reuters; NOAA Marine Forecasts


Index of Monthly Reports

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.

01/1977 (SEAN 02:01) Possible submarine eruption in October 1975

07/2002 (BGVN 27:07) Ash plumes during August 2002 indicate first activity since 1975

10/2002 (BGVN 27:10) Mid-August 2002 plumes, larger crater, and discolored water


Contents of Monthly Reports

All information contained in these reports is preliminary and subject to change.

01/1977 (SEAN 02:01) Possible submarine eruption in October 1975

[A table of possible submarine eruptions based on aerial observations of water discoloration by the Japanese Maritime Safety Agency included an entry for 30.38°N, 140.32°E, in October 1975. This location is ~11 km S of Tori-shima.]

Information Contacts: AFP; U.S. Defense Mapping Agency.

07/2002 (BGVN 27:07) Ash plumes during August 2002 indicate first activity since 1975

Around 1530 on 11 August 2002, a ship sailing near Tori-shima reported white smoke rising from the summit of the island. The Japanese Coast Guard inspected the island from the air during 1738-1818 and confirmed that the plume was rising 200-300 m from near the summit crater (Iwo-yama).

During an overflight on 12 August from 1145 to 1245 by the Japanese Meteorological Agency (JMA), an ash-laden plume was rising from the SW wall of the Iwo-yama summit crater. White plumes were also observed rising from the S to SE crater wall (figures 1 and 2). A vigorous ash plume rose 200-300 m above the crater every few minutes and drifted W to ~1 km above sea level. The summit area and the middle slope NNW of the summit were covered with ashfall deposits. The sea surface was discolored in an area up to 20 km W of the island. Izu-Tori-shima island is currently uninhabited.

Figure 1. Photo showing the Iwo-yama crater of Tori-shima volcano, taken around 1200 on 12 August 2002. Courtesy JMA.
Figure 2. Southern view of Tori-shima volcano showing ash plume from the summit crater, taken around 1200 on 12 August 2002. Courtesy JMA.

Information Contacts: Tomonori Kannno and Hitoshi Yamasato, Japanese Meteorological Agency (JMA), Volcanological Division, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: http://www.kishou.go.jp/ english/, Email: tkanno@met.kishou.go.jp, yamasato@met.kishou.go.jp).

10/2002 (BGVN 27:10) Mid-August 2002 plumes, larger crater, and discolored water

Following ship-based reports of activity at Tori-shima on 11 August 2002, scientists from the Japanese Meterological Agency overflew the area the next day when they observed and photographed ash plumes being erupted from the crater (BGVN 27:07). According to the Japan Coast Guard (via JMA), the activity continued as of 1200 on 14 August; the plume reached ~1.2-1.5 km above sea level on 13 August (figure 3), and ~900 m on 14 August. Emissions were observed from three active areas along the western inner-wall of the summit crater. The crater appeared to have widened. By 21 August, the Japan Coast Guard reported that Izu-Tori-shima no longer "smoked" and only weak steaming was seen in the southern portion of the crater. Faintly discolored sea surface was observed around the island.

Figure 3. Izu-Tori-Shima plume on 13 August 2002. Courtesy Air Force Weather Agency.

Information Contacts: Tomonori Kannno and Hitoshi Yamasato, Japanese Meteorological Agency (JMA), Volcanological Division, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: http://www.kishou.go.jp/english/, Email: tkanno@met.kishou.go.jp, yamasato@met.kishou.go.jp); Volcano Research Center (VRC), Earthquake Research Institute (ERI), University of Tokyo (URL: http://hakone.eri.u-tokyo.ac.jp/vrc/erup/torisima.html); U.S. Air Force Weather Agency, Offutt AFB, NE 68113-4039, USA.

The circular, 2.7-km-wide island of Izu-Torishima in the southern Izu Islands is capped by an unvegetated summit cone formed during an eruption in 1939. Fresh lava flows from this eruption form part of the northern coastline of the basaltic-to-dacitic edifice. The volcano is referred to as Izu-Torishima to distinguish it from the several other Japanese island volcanoes called Torishima ("Bird Island"). The main cone is truncated by a 1.5-km-wide caldera that contains two central cones, of which 394-m-high Ioyama is the highest. Historical eruptions have also occurred from flank vents near the north coast and offshore submarine vents. A 6-8 km wide submarine caldera lies immediately to the north.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
[ 2013 Jul 6 ] [ 2013 Jul 6 ] Uncertain 2  
2002 Aug 12 2002 Aug 20 Confirmed 2 Historical Observations Iwo-yama
1975 Oct 2 Unknown Confirmed 2 Historical Observations 9 km S of Torishima
1965 Nov 13 1965 Dec 5 ± 4 days Confirmed 0 Hydrophonic
1939 Aug 17 1939 Dec 26 ± 5 days Confirmed 3 Historical Observations North side of 1902 crater (Iwo-yama)
1902 Aug 7 1902 Aug 24 Confirmed 3 Historical Observations Komochi-yama, N & SW offshore flanks
1871 Apr Unknown Confirmed 0 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.



Synonyms
Tori-sima | Mitsugo-jima | Ponafidin | Izu-Tori-shima | Mitugo-zima


Cones
Feature Name Feature Type Elevation Latitude Longitude
Ioyama
    Iwo-yama
Cone 394 m 30° 28' 48" N 140° 18' 22" E
Komochi-yama
    Komoti-yama
Cone 361 m


Craters
Feature Name Feature Type Elevation Latitude Longitude
Hyogowan Crater
An August 12, 2002 photo shows an ash plume rising from the summit crater of Tori-shima volcano. The unvegetated cone of Iwo-yama, seen here from the south, was constructed during an eruption in 1939 within a 1.5-km-wide caldera that truncates the eroded flanks of the volcano. The circular, 2.7-km-wide island of Tori-shima is located in the southern Izu Islands. The volcano is also referred to as Izu-Tori-shima to distinguish it from the several other Japanese island volcanoes called Tori-shima ("Bird Island").

Photo courtesy of Japan Meteorological Agency, 2002.
The dark-colored lava flow along the coast in the foreground was emplaced during an eruption that began on August 17, 1939. A new cinder cone (Iwo-yama) was constructed in that year at the north end of the 1902 crater. Two lava flows reached the sea, the first at Hyogo-wan (the bay at the far right) and the second at Chitose Bay. Two persons were killed during the eruption, which ended at the end of December.

Copyrighted photo by Akira Takada (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.

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

Katsui Y (ed), 1971. List of the World Active Volcanoes. Volc Soc Japan draft ms, (limited circulation), 160 p.

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/.

Sugimoto T, Ishibashi H, Matsushima T, 2005. Petrological study of Torishima volcani, Izu Islands, Japan. Bull Volc Soc Japan (Kazan), 50: 87-101 (in Japanese with English abs).

Yuasa M, Murakami F, Saito E, Watanabe K, 1991. Submarine topography of seamounts on the volcanic front of the Izu-Ogasawara (Bonin) Arc. Bull Geol Surv Japan, 42: 703-743.

Volcano Types

Stratovolcano
Caldera
Pyroclastic cone(s)

Tectonic Setting

Subduction zone
Oceanic crust (< 15 km)

Rock Types

Major
Basalt / Picro-Basalt
Dacite
Andesite / Basaltic Andesite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
21
21
21
21

Affiliated Databases

Large Eruptions of Izu-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).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.