Akita-Komagatake

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 39.761°N
  • 140.799°E

  • 1637 m
    5369 ft

  • 283230
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Bulletin Report: January 2013 (BGVN 38:01)


Short lived plume rising to 50 m observed on 14 December 2011

The Japanese Meterological Agency (JMA) reported that a short-lived plume rose to 50 m above Akita-Komaga-take on 14 December 2011 and was recorded by a camera located to the N of Me-dake’s summit.

Aerial observations were conducted in cooperation with the Japan Ground Self Defense Force on 13 December. Areas of snow melt corresponded to geothermal areas that had been previously identified. No new geothermal areas were found.

An M 2.6 earthquake on 27 December at 1234 local time occurred ~2 km W of Me-dake, with a maximum JMA Seismic Intensity of 1 in Senboku-city, Akita Prefecture. The JMA Seismic Intensity scale, used in Japan and Taiwan is classified into 10 categories; 0 to 4, 5 weak, 5 strong, 6 weak, 6 strong, and 7. The seismicity around the area had temporarily increased, but then returned to baseline levels. No volcanic activity related to this seismicity was observed.

JMA reported no activity at Akita-Komaga-take in 2012.

Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/en).

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

Index of Bulletin 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.

09/1970 (CSLP 85-70) Frequent explosions send ash columns up to 400 m high

10/1970 (CSLP 85-70) As many as 400-500 daily eruptions; continuing as of 8 October

11/1970 (CSLP 85-70) Eruptions with explosion sounds, cinders, and smoke decrease in frequency

12/1970 (CSLP 85-70) Lava flow forms several new arms and is now 600 m long

01/1971 (CSLP 85-70) Explosions at the summit crater and lava flows from a new cinder cone

02/1971 (CSLP 85-70) Explosions decline rapidly and stop in late January

06/1971 (CSLP 85-70) No eruptive activity since 25 January

01/2013 (BGVN 38:01) Short lived plume rising to 50 m observed on 14 December 2011




Bulletin Reports

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


09/1970 (CSLP 85-70) Frequent explosions send ash columns up to 400 m high

Card 1017 (24 September 1970) Frequent explosions send ash columns up to 400 m high

"Akita-Komagatake volcano began a new eruption about 1400 TMT, 18 September. Columns of ash (up to 400m high) were emitted along with rumbling of the ground and drumming of explosion. On 19 September, the volcano was still active. Volcanic ashes and bombs were ejected at intervals of five to ten minutes. Explosions took place every 30 minutes. Occurrence of sulphurous acid gas was detected around the spot."

Information Contacts: Tokiko Tiba, Dept. of Geology, National Science Museum, Tokyo, Japan.

10/1970 (CSLP 85-70) As many as 400-500 daily eruptions; continuing as of 8 October

Card 1031 (14 October 1970) As many as 400-500 daily eruptions; continuing as of 8 October

Akita-Komagatake volcano began a new eruption on 18 September 1970 and is still active on 8 October. The first eruption with ash columns, explosion sounds, and incandescent cinders was observed at about 2130 JST on 18 September and a small lava flow appeared. The eruption crater is located at the upper flank of Medake, the central cone of this volcano, where weak fumarolic areas appeared about three weeks ago. This is the first eruption since 1932 (phreatic explosion). The crater is 10-15 m in diameter, and explosion smoke including ash and lava blocks went up about 400 m high at intervals of 4-5 minutes, and a 40-70-m-wide lava flow (andesite: by Drs. Aramaki and Ossaka) reached a length of about 600 m from the crater. These Strombolian-type eruptions take place 400-500 times a day and air-shocks caused by explosions are frequently recorded by an installed seismograph. Seismic observation of this volcano has been in operation by JMA, Tohoku University, and Tokyo University, and petrological, geographical, and other geophysical investigations are [conducted] by many volcanologists. No damage is reported.

Information Contacts: Yosihiro Sawada, JMA.

11/1970 (CSLP 85-70) Eruptions with explosion sounds, cinders, and smoke decrease in frequency

Card 1057 (27 November 1970) Eruptions with explosion sounds, cinders, and smoke decrease in frequency

Strombolian-type eruptions which began at medake in September are still active on 20 November 1970. The lava flow seems to be continuously supplied and was observed to be about 150 m wide and about 600 m long on 4 November. Eruptions with explosion sounds, cinders (about 500 m high, maximum), and volcanic smoke (about 400 m high, maximum) took place 400-500 times per day in the first part of October. This activity became weak in the latter part of the month and the number of eruptions per day was about 200. The rim of the crater at Medake was covered with new cinders or lava blocks, but no other remarkable change was observed.

Information Contacts: Yosihiro Sawada, JMA.

12/1970 (CSLP 85-70) Lava flow forms several new arms and is now 600 m long

Card 1074 (22 December 1970) Lava flow forms several new arms and is now 600 m long

Explosions at Medake, central cone of this double volcano, began to decrease in number in the middle of October. Explosions took place about 200 times per day with explosions sounds, smoke, and cinders (about 300 m high). But the effusion of new lava did not decline and several new arms of lava flow were formed. Therefore, the lava flow became about 200 m wide and about 600 m long. Volcanic tremors were sometimes recorded by the seismograph installed at a hot-spring spa about 4 km NW of the crater.

Information Contacts: Yosihiro Sawada, JMA.

01/1971 (CSLP 85-70) Explosions at the summit crater and lava flows from a new cinder cone

Card 1095 (20 January 1971) Explosions at the summit crater and lava flows from a new cinder cone

Strombolian-type volcanic explosions at the summit crater, Medake, have been taking place 100-200 times per day. besides, new lava has been flowing out from the foot of the new cinder cone.

Information Contacts: Yosihiro Sawada, JMA.

02/1971 (CSLP 85-70) Explosions decline rapidly and stop in late January

Card 1135 (23 February 1971) Explosions decline rapidly and stop in late January

Volcanic explosions at Medake crater had been taking place about 200 times per day until the middle of January 1971. Since the 17th, however, the activity declined rapidly and no volcanic explosion has been recorded by the seismograph installed at a point about 4 km NW of the active crater since 25 January.

Information Contacts: Yosihiro Sawada, JMA.

06/1971 (CSLP 85-70) No eruptive activity since 25 January

Card 1227 (01 June 1971) No eruptive activity since 25 January

"No eruption has occurred since 25 January this year. It was reported that abnormal phenomena such as explosion sounds, rumbling, etc. were observed in the middle of April, but the information was not confirmed. According to the field observation by the Tazawa-ko Town Office on the 27 April, no active state in and near the crater where volcanic eruptions had taken place until the end of this January was observed, but a weak fumarolic area (about 250 m2) was seen near the crater. Maximum geothermal temperature obtained in this fumarolic area was 80°C. Steaming on the lava flow (about 600 m in length and about 3,600,000 tons in volume) was observed at some places, too.)"

Information Contacts: Seismological Division, JMA.

01/2013 (BGVN 38:01) Short lived plume rising to 50 m observed on 14 December 2011

The Japanese Meterological Agency (JMA) reported that a short-lived plume rose to 50 m above Akita-Komaga-take on 14 December 2011 and was recorded by a camera located to the N of Me-dake’s summit.

Aerial observations were conducted in cooperation with the Japan Ground Self Defense Force on 13 December. Areas of snow melt corresponded to geothermal areas that had been previously identified. No new geothermal areas were found.

An M 2.6 earthquake on 27 December at 1234 local time occurred ~2 km W of Me-dake, with a maximum JMA Seismic Intensity of 1 in Senboku-city, Akita Prefecture. The JMA Seismic Intensity scale, used in Japan and Taiwan is classified into 10 categories; 0 to 4, 5 weak, 5 strong, 6 weak, 6 strong, and 7. The seismicity around the area had temporarily increased, but then returned to baseline levels. No volcanic activity related to this seismicity was observed.

JMA reported no activity at Akita-Komaga-take in 2012.

Information Contacts: Japan Meteorological Agency (JMA), 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan (URL: http://www.jma.go.jp/jma/en).
Download or Cite this Report

Two calderas partially filled by basaltic cones cut the summit of Akita-Komagatake volcano. The larger southern caldera is 1.5 x 3 km wide and has a shallow sloping floor that is drained through a narrow gap cutting the SW caldera rim. On its northern side the southern caldera borders a smaller more circular 1.2-km-wide caldera, whose rim is breached widely to the NE. The two calderas were formed following explosive eruptions at the end of the Pleistocene, between about 13,500 and 11,600 years ago. Two cones, Medake and Kodake, occupy the NE corner of the southern caldera, whose long axis trends NE-SW. The 1637-m-high Komagatake (also known as Onamedake) cone within the northern caldera is highest point, and has produced lava flows to the north and east; it has a 100-m-wide summit crater. Small-scale historical eruptions have occurred from cones and fissure vents inside the southern caldera. The temperatures of geothermal areas increased beginning in 2005, and some fumarolic plumes were observed in 2011-12.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1970 Sep 18 1971 Jan 26 Confirmed 2 Historical Observations Me-dake
1932 Jul 21 1932 Jul 24 Confirmed 2 Historical Observations Ishibora (south flank of Me-dake)
1902 Unknown Confirmed 1 Historical Observations Yoko-dake
1890 Dec 1891 Jan Confirmed 2 Historical Observations
1100 (?) Unknown Confirmed 2 Tephrochronology
0807 (?) Unknown Confirmed 3 Historical Observations AK-1 tephra
0400 ± 500 years Unknown Confirmed   Tephrochronology Me-dake
0050 BCE ± 200 years Unknown Confirmed 2 Radiocarbon (corrected) AK-2 tephra
0200 BCE ± 200 years Unknown Confirmed   Radiocarbon (corrected) Minami-dake, Ko-dake
0350 BCE ± 200 years Unknown Confirmed 3 Radiocarbon (corrected) AK-3 tephra
1450 BCE ± 50 years Unknown Confirmed   Radiocarbon (corrected) AK-5, AK-4 tephra layers
5950 BCE ± 200 years Unknown Confirmed 3 Radiocarbon (corrected) AK-6 tephra
6150 BCE ± 300 years Unknown Confirmed   Tephrochronology
6350 BCE ± 200 years Unknown Confirmed 3 Radiocarbon (corrected) AK-7 tephra
7100 BCE ± 900 years Unknown Confirmed   Tephrochronology
7850 BCE ± 200 years Unknown Confirmed 4 Radiocarbon (corrected) AK-8, Horikiri tephra
8300 BCE ± 300 years Unknown Confirmed 4 Tephrochronology AK-9, Arasawa tephra
8800 BCE ± 300 years Unknown Confirmed 3 Tephrochronology AK-11, AK-10 tephra layers

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

Komakata-yama | Koma-dake | Akita-Komaga-take

Cones

Feature Name Feature Type Elevation Latitude Longitude
Katakura-yama Cone
Ko-dake Cone 1400 m
Me-dake Cone 1500 m
Omae-dake
    Onamedake
Cone 1637 m

Craters

Feature Name Feature Type Elevation Latitude Longitude
Ishibora Fissure vent
Nambu Caldera
Otsubo-no-ike
    Otubo-no-ike
Crater
Omae-dake cone and the small pond Amida-ike are located at the NE end of the summit crater complex of Akita-Komaga-take volcano. The pyroclastic cone Omae-dake (also known as Komaga-take) forms the highest point of the volcano and has produced lava flows to the north and east. This photo is taken from the NE rim of an elliptical 1.5 x 3 km caldera partially filled by basaltic cones. Historical eruptions have occurred from cones and fissure vents inside the caldera.

Photo by Ichio Moriya (Kanazawa University).

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.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

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.

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/.

Wachi T, Doi N, Koshiya S, 1997. Tephra stratigraphy and eruptive activities of the Akita-Komagatake volcano. Bull Volc Soc Japan (Kazan), 42: 17-34 (in Japanese with English abs).

Yagi K, Takeshita H, Oba Y, 1972. Petrological study on the 1970 eruption of Akita-Komagatake volcano, Japan. Hokkaido Univ Fac Sci Jour, 15: 109-138.

Volcano Types

Stratovolcano(es)
Caldera(s)
Pyroclastic cone(s)

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Basalt / Picro-Basalt
Andesite / Basaltic Andesite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
376
3,864
216,708
2,521,611

Affiliated Databases

Large Eruptions of Akita-Komagatake 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.