Shikotsu

Photo of this volcano
Google Earth icon
  Google Earth Placemark
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 42.688°N
  • 141.38°E

  • 1320 m
    4330 ft

  • 285040
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Shikotsu.

The Global Volcanism Program has no Weekly Reports available for Shikotsu.

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.

06/1978 (SEAN 03:06) Explosive eruption with small pyroclastic flow after 10 years of increasing seismicity

07/1978 (SEAN 03:07) No new explosions; seismicity declines to normal

12/1978 (SEAN 03:12) Two small ash eruptions

01/1979 (SEAN 04:01) Ash eruptions continue

02/1979 (SEAN 04:02) Small ash eruptions continue; seismicity increases sharply

03/1979 (SEAN 04:03) Small ash eruptions and increased seismicity continue

04/1979 (SEAN 04:04) More ash eruptions but declining seismicity

05/1979 (SEAN 04:05) Seismicity and number of explosions decline

06/1979 (SEAN 04:06) Small ash eruption but decline in seismicity persists

07/1979 (SEAN 04:07) Seismicity increases, but no explosions

08/1979 (SEAN 04:08) No explosions; seismicity declines

11/1979 (SEAN 04:11) Brief increase in seismicity, but no eruption

12/1980 (SEAN 05:12) Seismicity increases

01/1981 (SEAN 06:01) Seismicity continues to increase

02/1981 (SEAN 06:02) Sharp increase in seismicity

03/1981 (SEAN 06:03) Seismicity declines without expected eruption

04/1981 (SEAN 06:04) Minor ash emission during February seismic peak

02/1988 (SEAN 13:02) Earthquake swarms

07/1996 (BGVN 21:07) Seismic activity increases

08/1996 (BGVN 21:08) Tarumai stratovolcano on the caldera's rim is site of 65 earthquakes


Contents of Monthly Reports

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

All times are local (= UTC + 9 hours)

06/1978 (SEAN 03:06) Explosive eruption with small pyroclastic flow after 10 years of increasing seismicity

Tarumai exploded on 14 May at 2253, accompanied by volcanic tremor. A slight ashfall was observed 10 km NNE of the summit crater and a small pyroclastic flow consisting of pumiceous ash and blocks traveled 150 m SE from the vent. Sixteen hours after the eruption, geologists measured a temperature of 200°C at the base of the pyroclastic flow (30 cm below the surface). Smaller explosions occurred on 17 May, mantling the vent area with 1 cm of new ash. No further explosions had been observed as of 7 June.

Tarumai, which last erupted in 1955, is characterized by conspicuous earthquake swarms, followed by explosive eruptions of andesitic magma, then lava dome extrusion. The number of earthquakes at Tarumai has been increasing irregularly for the past 10 years and increased sharply in the first five months of 1978 (figure 1). No eruption was associated with the somewhat smaller peak in seismicity that occurred in 1975.

Figure 1. Monthly seismicity recorded at JMA's Tarumai Observatory, January 1978-June 1979. Arrows represent ash eruptions. Courtesy of JMA.

Further Reference. Katsui, Y., Onuma, K., Niida, K., Suzuki, T., and Kondo, Y., 1979, Eruption of Tarumai volcano in May 1978: Bulletin of the Volcanological Society of Japan, v. 24, no. 2, p. 31-40.

Information Contacts: JMA, Tokyo; D. Shackelford, CA.

07/1978 (SEAN 03:07) No new explosions; seismicity declines to normal

As of early July, no eruptive activity had been observed since the explosions of 14 and 17 May. Seismicity decreased to its normal level in mid-June after a 10-year increase preceding the May explosions.

Information Contact: JMA, Tokyo.

12/1978 (SEAN 03:12) Two small ash eruptions

Tarumai erupted ash from 0910 to 0920 on 12 December. The ash cloud rose 200 m above the vent, which was also the source of small explosions on 14 and 17 May. Ash slightly darkened the snow in the summit area, but did not reach the foot of the volcano. A second ash eruption occurred on 16 December, with ashfall again restricted to the summit area. Seismicity remained at a low level (table 1).

Table 1. Monthly seismicity at Shikotsu (Tarumai) in 1978. Courtesy of JMA.

    1978         Events

    January        22
    February       39
    March          95
    April         170
    May           298
    June          112
    July           26
    August         18
    September      13
    October        17
    November       13
    December      [21]

Information Contact: JMA, Tokyo.

01/1979 (SEAN 04:01) Ash eruptions continue

Ash eruptions continued through early January. Ash was ejected on 16, 26, and 29 December and on 5 January, falling on the summit area. Seismicity remained at normal levels through December.

Information Contact: JMA, Tokyo.

02/1979 (SEAN 04:02) Small ash eruptions continue; seismicity increases sharply

Ash eruptions continued through January. Ash was ejected on 5, 22, 23, and 27 January, darkening snow in the summit area, but no ash reached the foot of the volcano.

Local seismicity increased sharply about 10 January, after several months of relative quiet. An irregular increase in seismic activity has persisted since 1967.

Information Contact: JMA, Tokyo.

03/1979 (SEAN 04:03) Small ash eruptions and increased seismicity continue

Ash was ejected on 5, 8, 19, and 25-28 February, continuing the series of small explosions that resumed 12 December. The ash darkened snow in the summit area, but did not reach the foot of the volcano. The number of recorded local earthquakes increased from 201 in January to 427 in February.

Information Contact: JMA, Tokyo.

04/1979 (SEAN 04:04) More ash eruptions but declining seismicity

Ash eruptions continued in March. Ash fell on the summit area on 1, 2, 4, 6, and 8 March but did not reach the foot of the volcano. Seismicity declined considerably in March, but remained slightly above the monthly total for January.

Information Contact: JMA, Tokyo.

05/1979 (SEAN 04:05) Seismicity and number of explosions decline

Eruptive and seismic activity declined substantially in April. Only one [ash eruption] took place in April, on the 13th, causing a small ashfall in the summit area. The monthly number of recorded earthquakes dropped from 223 in March to 70 in April.

Information Contact: JMA, Tokyo.

06/1979 (SEAN 04:06) Small ash eruption but decline in seismicity persists

The decline in activity continued through May. A single small ash eruption occurred in May, on the 11th. Ash fell in the summit area but not reach the foot of the volcano. Monthly recorded earthquakes decreased slightly from 70 in April to 66 in May, but the number of tremor events dropped more sharply, from more than 40 to 9. The tremor events, each lasting a few minutes, were thought to be generated by vigorous activity at a vent. The strongest of this activity was visible from the base of the volcano.

Information Contact: JMA, Tokyo.

07/1979 (SEAN 04:07) Seismicity increases, but no explosions

No explosions or tremor events were recorded in June. However, the number of local earthquakes, which had been declining since March, increased in June.

Information Contact: JMA, Tokyo.

08/1979 (SEAN 04:08) No explosions; seismicity declines

The number of recorded earthquakes declined to 58 in July after rising sharply to 142 in June. No explosions were observed in July, nor were any tremor events, which are presumably generated by [ash ejection].

Information Contact: JMA, Tokyo.

11/1979 (SEAN 04:11) Brief increase in seismicity, but no eruption

An increase in the number of local earthquakes and a resumption of tremor events occurred in mid-September, but no eruption was observed. In October, seismicity returned to normal levels and no tremor events were recorded.

Information Contact: JMA, Tokyo.

12/1980 (SEAN 05:12) Seismicity increases

Seismic activity increased in November after about one and a half years of quiet.

Information Contact: JMA, Tokyo.

01/1981 (SEAN 06:01) Seismicity continues to increase

Seismic activity increased again to more than 400 recorded events during January. No eruption has yet been observed. About 200 events per month were recorded in November and December, after over a year of fewer than 50 events per month.

Information Contact: JMA, Tokyo.

02/1981 (SEAN 06:02) Sharp increase in seismicity

In February, 1,121 seismic events were recorded, the most in any month since 1967, when JMA began routine measurements at the volcano. Seismicity has irregularly but gradually increased in the past 14 years (figure 2). No eruption has occurred during the current increase in seismicity.

Figure 2. Yearly means of Tarumai's monthly seismicity, 1967-80. Courtesy of JMA.

Information Contact: JMA, Tokyo.

03/1981 (SEAN 06:03) Seismicity declines without expected eruption

Local seismicity began to increase in November 1980 and the number of events per month reached 1,211 in February 1981 (figure 3). Seismicity began a gradual decline in early March and by mid-March had reached the usual average of fewer than three recorded earthquakes per day.

Figure 3. Monthly numbers of days with eruptions (top), tremor events (center), and recorded earthquakes (bottom) at Tarumai, January 1978-March 1981. Courtesy of JMA.

Only 87 events were recorded in March. Although the December 1978-May 1979 eruption accompanied the last major increase in seismicity, no eruption has occurred during the current, much larger increase [but see 06:04].

Information Contact: JMA, Tokyo.

04/1981 (SEAN 06:04) Minor ash emission during February seismic peak

Seismicity declined to its usual level of fewer than three recorded earthquakes per day in March and remained at this level through April. Although no volcanic activity apparently had accompanied the peak of seismicity in February (1,211 events), subsequent investigation revealed that a weak steam explosion had occurred on 27 February or a few days earlier.

On the morning of 27 February an All Nippon Airways crew reported that they saw radially darkened snow on the SE part of the summit area. Yoshio Katsui visited the summit on 9 April and found a single layer of gray ash in the snow. The ash layer was only 0.3-0.6 mm thick at the crater rim. The total volume of ejecta was estimated to be no more than 400 m3.

Information Contacts: JMA, Tokyo; Y. Katsui, Hokkaido Univ.

02/1988 (SEAN 13:02) Earthquake swarms

Local earthquake swarms occurred 24 January-18 February. The JMA seismometer, 1.1 km NE of the summit cone, recorded 30 events in January and 124 in February. Epicenters were located at the NW somma using data from five Hokkaido University seismometers. A white plume constantly rose ~100 m.

Tarumai's strongest earthquake swarm of the past two decades began in late 1980, peaking in February 1981, when more than 1,200 shocks were recorded. Late that month ~400 m3 of ash was deposited near the crater by a very small eruption. Seismicity then declined, and the number of local events has averaged <10/month in the last few years (figure 4).

Figure 4. Monthly number of earthquakes at Tarumai, January 1967-January 1988. Courtesy of JMA.

Information Contact: JMA.

07/1996 (BGVN 21:07) Seismic activity increases

The number of volcanic earthquakes beneath Tarumai stratovolcano (on the rim on Shikotsu caldera) increased in June and July. There were 13 events on both 8 and 10 June. A total of 64 earthquakes was recorded in July.

Information Contacts: Volcanological Division, Japan Meteorological Agency, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan

08/1996 (BGVN 21:08) Tarumai stratovolcano on the caldera's rim is site of 65 earthquakes

The number of volcanic earthquakes beneath Tarumai stratovolcano increased during the second half of August. A total of 65 earthquakes was recorded in August.

Information Contacts: Volcanological Division, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan.

The 13 x 15 km Shikotsu caldera, largely filled by the waters of Lake Shikotsu, was formed during one of Hokkaido's largest Quaternary eruptions about 31-34,000 years ago. The small andesitic Tarumai stratovolcano was then constructed on its SE rim and has been Hokkaido's most active volcano in historical time. Pyroclastic-flow deposits from Tarumai extend nearly to the Pacific coast. Two other Holocene post-caldera volcanoes, Fuppushi (adjacent to Tarumai) and Eniwa (on the opposite side of the caldera), occur on a line trending NW from Tarumai, and were constructed just inside the caldera rim. Minor eruptions took place from the summit of Eniwa volcano as late as the 17th century. The summit of Tarumai contains a small 1.5-km-wide caldera formed during two of Hokkaido's largest historical eruptions, in 1667 and 1739. Tarumai is now capped by a flat-topped summit lava dome that formed in 1909.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1981 Feb 27 (in or before) Unknown Confirmed 0 Historical Observations Tarumai
1978 Dec 12 1979 May 11 Confirmed 1 Historical Observations Tarumai (SE foot of summit dome)
1978 May 14 1978 May 17 Confirmed 1 Historical Observations Tarumai (SE foot of summit dome)
1954 Nov 19 1955 Feb 14 Confirmed 1 Historical Observations Tarumai
1954 May 2 1954 May 2 Confirmed 1 Historical Observations Tarumai
1953 Sep 14 (?) 1953 Sep 14 (?) Confirmed 1 Historical Observations Tarumai
1951 Jul 28 1951 Jul 28 Confirmed 2 Historical Observations Tarumai
1951 Jan 29 1951 Jan 29 Confirmed 2 Historical Observations Tarumai
[ 1944 Nov 25 ] [ 1944 Nov 25 ] Uncertain 1   Tarumai
1944 Jul 2 1944 Jul 2 Confirmed 1 Historical Observations Tarumai
1936 Nov 15 1936 Nov 26 Confirmed 1 Historical Observations Tarumai
1936 Apr 19 1936 Apr 19 Confirmed 1 Historical Observations Tarumai
1933 Dec 1 1933 Dec 14 Confirmed 2 Historical Observations Tarumai (east-west summit fissure)
1931 Oct 11 1931 Oct 24 Confirmed 1 Historical Observations Tarumai
1928 Sep 6 1929 Feb 10 Confirmed 1 Historical Observations Tarumai
1928 Jan 7 1928 Jan 7 Confirmed 2 Historical Observations Tarumai
1926 Oct 19 1926 Oct 30 Confirmed 2 Historical Observations Tarumai
1923 Feb 1923 Aug 23 Confirmed 1 Historical Observations Tarumai
1921 Jul 6 1921 Jul 6 Confirmed 1 Historical Observations Tarumai
1920 Jul 17 1920 Jul 23 Confirmed 1 Historical Observations Tarumai
1919 May 4 1919 May 4 Confirmed 2 Historical Observations Tarumai
1918 Jun 13 1918 Jul 31 Confirmed 1 Historical Observations Tarumai
1917 Apr 30 1917 May 12 Confirmed 2 Historical Observations Tarumai (east-west summit fissure)
1909 Jan 11 1909 Apr 22 Confirmed 3 Historical Observations Tarumai
1894 Aug 17 1894 Aug 17 Confirmed 2 Historical Observations Tarumai
1894 Feb 8 1894 Feb 8 Confirmed 2 Historical Observations Tarumai
1887 Sep 3 1887 Oct 8 Confirmed 2 Historical Observations Tarumai
1886 Apr 13 1886 Apr 28 Confirmed 2 Historical Observations Tarumai
1885 Jan 4 1885 Mar Confirmed 2 Historical Observations Tarumai
1883 Oct 7 1883 Nov 5 Confirmed 2 Historical Observations Tarumai
1874 Feb 8 1874 Feb 16 Confirmed 3 Historical Observations Tarumai
[ 1871 Dec 25 ] [ 1871 Dec 28 ] Uncertain 2   Tarumai
1867 Sep 8 Unknown Confirmed 2 Historical Observations Tarumai
1804 1817 Confirmed 3 Historical Observations Tarumai
1739 Aug 19 1739 Aug 31 Confirmed 5 Historical Observations Tarumai, Ta-a tephra
1707 ± 30 years Unknown Confirmed 2 Tephrochronology Eniwa (crater 3)
1667 Sep 23 1667 Sep 26 (?) Confirmed 5 Historical Observations Tarumai, Ta-b tephra
1550 ± 75 years Unknown Confirmed 2 Radiocarbon (corrected) Eniwa (crater 2)
1500 ± 150 years Unknown Confirmed 2 Radiocarbon (corrected) Eniwa (crater 1)
0050 BCE (?) Unknown Confirmed 3 Tephrochronology Tarumai, Ta-c3 tephra
0100 BCE ± 100 years Unknown Confirmed 2 Radiocarbon (corrected) Eniwa volcano (east side of summit)
0550 BCE (?) Unknown Confirmed 5 Radiocarbon (uncorrected) Tarumai, Ta-c1, Ta-c2 tephras
6950 BCE (?) Unknown Confirmed 5 Radiocarbon (uncorrected) Tarumai, Ta-d tephra

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
Sikotu


Cones
Feature Name Feature Type Elevation Latitude Longitude
Eniwadake
    Eniwa
Stratovolcano 1320 m 42° 47' 27" N 141° 17' 20" E
Fuppushidake
    Huppusi-dake
    Fuppushi-dake
Stratovolcano 1103 m
Kitayama
    Kita-yama
Stratovolcano 931 m
Tarumaesan
    Tarumai
Stratovolcano 1038 m 42° 41' 17" N 131° 22' 49" E


Craters
Feature Name Feature Type Elevation Latitude Longitude
Shikotsu Caldera
Tarumai volcano, seen here from the SW, is a small stratovolcano that is capped by a flat-topped lava dome formed during an eruption in 1909. The dome was emplaced in a small caldera, the shallow bowl at the summit, that was created during major explosive eruptions in 1667 and 1739.

Photo by Tom Simkin, 1981 (Smithsonian Institution).
Tarumai volcano is a small stratovolcano constructed on the SE rim of the 13 x 15 km Shikotsu caldera. The summit of Tarumai contains a small 1.5-km-wide caldera that was formed during two of Hokkaido's largest historical eruptions, in 1667 and 1739. It is capped by a flat-topped summit lava dome that grew in 1909. Tarumai has been Hokkaido's most active volcano in historical time. Two other Holocene post-caldera volcanoes occur at Shikotsu, Fuppushi (adjacent to Tarumai) and Eniwa, on the opposite side of the caldera.

Photo by Ichio Moriya (Kanazawa University).
Shikotsu caldera, seen in an aerial view from the SE with Yotei volcano on the center horizon, is a 13 x 15 km caldera filled by Lake Shikotsu. Following formation of the caldera more than 30,000 years ago, three small stratovolcanoes were constructed along a NW-trending line cutting across the caldera. Snow-capped Tarumai volcano (left center) grew near the SE rim of the caldera, along with Fuppushi volcano to its right. A third volcano, Eniwa, was constructed on the NW caldera rim, at the far side of the lake.

Photo by Ichio Moriya (Kanazawa University).
These thick pyroclastic-flow deposits were produced during the major eruption that formed the 13 x 15 km Shikotsu caldera. The eruption produced 125 cu km of rhyolitic tephra and pyroclastic flows. Pyroclastic flows traveled as far as 40 km from the volcano, reaching the Pacific coast over a broad area. This outcrop is located 15 km ENE of the caldera.

Photo by Ryuta Furukawa, 1993 (Hokkaido University).
Volcanoes and calderas fill much of this NASA Shuttle Radar Tomography (SRTM) image of southern Hokkaido with north to the upper left. Usu volcano (bottom center) lies south of Toya caldera. The smaller caldera to the right along the Pacific Ocean is Kuttara. Tarumai and Eniwa volcanoes lie on the estern and western sides, respectively, of Shikotsu caldera (upper right). The conical white peak at left-center is Yotei volcano; Niseko volcano is along the ridge to its left. The city of Sapporo lies at the base of the mountains (top-center).

NASA Shuttle Radar Tomography Mission image, 2000 (http://earthobservatory.nasa.gov/).

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, Yokoyama I, Murozumi M, 1981b. Noboribetsu Spa. In: Katsui Y (ed) {Symp Arc Volc Field Excur Guide to Usu and Tarumai Volcanoes and Noboribetsu Spa, Part 3}, Tokyo: Volc Soc Japan, p 55-64.

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.

Nakagawa M, Furukawa R, Yoshimoto M, 2003. Calderas and active volcanoes in southwestern Hokkaido. IUGG 2003 Field Trip Guidebook, Volc Soc Japan, p 1-35.

Nakagawa M, Masuda K, Katsui Y, 1994. Recent eruptions of Eniwa volcano, post-Shikotsu caldera, southwestern Hokkaido. Bull Volc Soc Japan (Kazan), 39: 237-241.

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/.

Volcano Types

Caldera
Stratovolcano(es)
Lava dome

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Andesite / Basaltic Andesite
Dacite
Rhyolite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
130,474
130,474
316,816
3,096,376

Affiliated Databases

Large Eruptions of Shikotsu 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.