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Akita-Yakeyama

Photo of this volcano
  • Japan
  • Stratovolcano
  • 1997 CE
  •  
  • Country
  • Primary Volcano Type
  • Last Known Eruption
  •  
  • 39.964°N
  • 140.757°E

  • 1366 m
    4482 ft

  • 283260
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Bulletin Report: October 1997 (BGVN 22:10) Citation IconCite this Report

Phreatic explosion on 16 August

According to a Japan Meteorological Agency (JMA) volcanic advisory issued in the evening of 16 August, a tourist reported a small-scale phreatic explosion at the Karanuma ("Empty Pond") crater near the summit. The explosion occurred at about noon on 16 August. Seismometers at the volcano recorded volcanic tremors during 1053-1204; high numbers of volcanic earthquakes were recorded in the days following the explosion (table 1). JMA estimated that the epicenters were just below the summit.

Table 1. Seismic activity at Akita-Yake-yama during 16-25 August 1997. Reported on the Volcano Research Center's Current Eruptions in Japan website from JMA reports for 22 and 25 August.

Date Volcanic earthquakes Tremors
16 Aug 1997 62 2
17 Aug 1997 81 1
18 Aug 1997 71 0
19 Aug 1997 448 1
20 Aug 1997 226 0
21 Aug 1997 27 0
22 Aug 1997 14 0
23 Aug 1997 18 0
24 Aug 1997 14 0
25 Aug 1997 10 0 (by 1500)

A 17 August JMA report detailed the discovery of a new crater 20 m in diameter on the SE rim of Karanuma Crater. Eruptive material including fragments up to 20 cm in diameter were found around the new crater, and volcanic ash "pastes" had been sprayed ~300 m to the S. The report noted that the new crater no longer emitted an eruption cloud on 17 August.

T. Oba and T. Hasenaka, geologists at Tohoku University, conducted a field inspection on 17 August. They reported that the new crater was quiet, and that it had a depth of ~30 m. Fragments up to 30 cm across had been thrown ~25 m away from the crater, but no juvenile materials were included. Ash deposits on the ridge 20-30 m S of the new crater were 4-5 mm thick. The scientists suggested that the 16 August eruption may have created a "new" crater within an old crater formed in 1949, because the volume of recently erupted material was too small to account for the total volume of the crater.

Shintaro Hayashi, a geologist at Akita University, conducted a field inspection on 18 August; he estimated the volume of fallout from the new crater to be ~1,000 m3. He also reported that a mud flow was generated just before the 16 August explosion issued from small depressions just below the new crater (figure 1). The mud was deposited around the depressions, having flowed part of the way down to the crater floor. The total volume of the mud-flow deposit was estimated at ~20,000 m3.

Figure (see Caption) Figure 1. Map of Akita-Yake-yama showing recent craters. Craters A1-A3 were formed in 1949; craters A, B1, and B2 were formed in 1997. Heavy lines indicate ash isopachs; dots indicate ash sampling sites. Courtesy of Shintaro Hayashi, Akita University.

On 20-21 August, new seismometers were installed near the summit and N slope of the volcano; also installed were a microphone on the W foot and cameras (color, high resolution monochromatic, and infrared) on the E foot. Signals are telemetered to Sendai and Akita.

On 22 August, Tatsunori Soya, of the Geological Survey of Japan, drew attention to a document written by the late Prof. H. Tsuya. The document, which appeared in the Tamagawa Hot Spring Study Group's 10th Anniversary Report (1954), describes explosions in 1949, 1950, and 1951 at Akita-Yake-yama; the last two were not officially documented. According to the report, large explosion craters (C1-C4), including the Karanuma crater (C1), existed before the 1949 eruption. Eruptions in 1949 occurred on the E margin of the Karanuma crater, resulting in the formation of craters designated A1, A2, and A3. Although no one in the hot springs area 3 km E of the summit reported hearing an explosion or feeling earthquakes, the eruption products were ~1 m thick along the rim of the A1 crater and contained old lava blocks up to 1 m across. Another explosion occurred at the A1 crater in February 1951; as a result, A1 crater widened to become as much as 50 m across. In terms of volume, the 1951 explosion was smaller than the 1949 eruption. S. Hayashi proposed that the present explosion occurred in A2-A1, and mud spouted out from the A3 crater (figure 1).

Information Contacts: Shintaro Hayashi, Faculty of Education, Akita University, 1-1 Tegata-Gakuen-Cho, Akita 010, Japan; Noritake Nishide, Sendai District Meteorological Observatory, Japan Meteorological Agency, 1-3-5 Gorin, Miyagino-ku, Sendai 983 Japan; Volcano Research Center, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html); Tatsunori Soya, Volcanology Section, Environmental Geology Department, Geological Survey of Japan, 1-1-3, Higashi, Tsukuba, Ibaraki, 305 Japan; Tsukasa Ohba and Toshiaki Hasenaka, Institute of Mineralogy, Petrology, and Economic Geology, Faculty of Science, Tohoku University, Miyagi, Sendai 980-77, Japan.

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

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.

05/1997 (BGVN 22:05) Landslide, explosion, mud- and debris-flows, and tephra

10/1997 (BGVN 22:10) Phreatic explosion on 16 August




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


May 1997 (BGVN 22:05) Citation IconCite this Report

Landslide, explosion, mud- and debris-flows, and tephra

On 11 May, rapid movement of an older landslide was followed by a steam explosion that triggered mud flows and a small tephra emission. The event occurred at Sumikawa-Onsen (a hot spring resort) at the foot of Akita-Yakeyama, ~4 km NE of the summit. The following is based on a report by Shintaro Hayashi.

Although the landslide began moving a few days before 11 May, the sliding accelerated 20 minutes before the explosion. A field party saw the fast-moving landslide and took refuge prior to 0800 on 11 May. The explosion was witnessed at 0800 by a pilot flying over the area; he saw a water-and-steam column rising like a geyser, followed within seconds by black smoke emissions.

The explosion, heard as far as 1.4 km away, triggered a mudflow along the Akagawa River and eventually developed into a debris flow downstream. The field party noticed a thin coat of ash covering the mudflow deposits; they concluded that the tephra had issued from the explosion site.

Hayashi suggested that the explosion was triggered by sudden depressurization of a hot water reservoir under the hot spring due to removal of the overlying debris. The depressurization led to sudden boiling, generating sufficient steam pressure to explode. The volume of erupted material was estimated to be between 1,000 and 10,000 m3.

According to Hiroyuri Hamaguchi the precursory vibration and tremor were recorded by a short-period seismometer 1 km NNE of the hot spring. The landslide was as large as 500 m wide, 150 m long, and 500 m deep. After 2000 on 10 May, tremors of increasing amplitude built up. They declined by midnight and then returned at 0400 on 11 May. A maximum amplitude was reached at 0732, followed by a hiatus during 0753-0757. Short- and long-period events took place at 0757 and 0758, respectively.

Hayakawa reported that two hotels at the foot of Akita Yakeyama were completely destroyed by the landslide and lahar; however, there were no casualties because the staff and guests had evacuated. Air photos taken on 12 May by Asia Air Survey Co. can be seen on the internet.

Information Contacts: Shintaro Hayashi, Faculty of Education, Akita University, 1-1 Tegata-Gakuen-Cho, Akita 010, Japan; Hiroyuki Hamaguchi, Faculty of Science, Tohoku University, Sendai 980-77, Japan; Yukio Hayakawa, Faculty of Education, Gunma University, 4-2 Aramaki-machi, Mae-bashi-chi, Gunma 371, Japan (URL: http://www.hayakawayukio.jp/); Tatsuro Chiba, Dept of Disaster Prevention, Asia Air Survey Co., 4-2-18 Shinjuku, Shinjuku-ku, Tokyo 160, Japan (URL: http://www.ajiko.co.jp/en/).


October 1997 (BGVN 22:10) Citation IconCite this Report

Phreatic explosion on 16 August

According to a Japan Meteorological Agency (JMA) volcanic advisory issued in the evening of 16 August, a tourist reported a small-scale phreatic explosion at the Karanuma ("Empty Pond") crater near the summit. The explosion occurred at about noon on 16 August. Seismometers at the volcano recorded volcanic tremors during 1053-1204; high numbers of volcanic earthquakes were recorded in the days following the explosion (table 1). JMA estimated that the epicenters were just below the summit.

Table 1. Seismic activity at Akita-Yake-yama during 16-25 August 1997. Reported on the Volcano Research Center's Current Eruptions in Japan website from JMA reports for 22 and 25 August.

Date Volcanic earthquakes Tremors
16 Aug 1997 62 2
17 Aug 1997 81 1
18 Aug 1997 71 0
19 Aug 1997 448 1
20 Aug 1997 226 0
21 Aug 1997 27 0
22 Aug 1997 14 0
23 Aug 1997 18 0
24 Aug 1997 14 0
25 Aug 1997 10 0 (by 1500)

A 17 August JMA report detailed the discovery of a new crater 20 m in diameter on the SE rim of Karanuma Crater. Eruptive material including fragments up to 20 cm in diameter were found around the new crater, and volcanic ash "pastes" had been sprayed ~300 m to the S. The report noted that the new crater no longer emitted an eruption cloud on 17 August.

T. Oba and T. Hasenaka, geologists at Tohoku University, conducted a field inspection on 17 August. They reported that the new crater was quiet, and that it had a depth of ~30 m. Fragments up to 30 cm across had been thrown ~25 m away from the crater, but no juvenile materials were included. Ash deposits on the ridge 20-30 m S of the new crater were 4-5 mm thick. The scientists suggested that the 16 August eruption may have created a "new" crater within an old crater formed in 1949, because the volume of recently erupted material was too small to account for the total volume of the crater.

Shintaro Hayashi, a geologist at Akita University, conducted a field inspection on 18 August; he estimated the volume of fallout from the new crater to be ~1,000 m3. He also reported that a mud flow was generated just before the 16 August explosion issued from small depressions just below the new crater (figure 1). The mud was deposited around the depressions, having flowed part of the way down to the crater floor. The total volume of the mud-flow deposit was estimated at ~20,000 m3.

Figure (see Caption) Figure 1. Map of Akita-Yake-yama showing recent craters. Craters A1-A3 were formed in 1949; craters A, B1, and B2 were formed in 1997. Heavy lines indicate ash isopachs; dots indicate ash sampling sites. Courtesy of Shintaro Hayashi, Akita University.

On 20-21 August, new seismometers were installed near the summit and N slope of the volcano; also installed were a microphone on the W foot and cameras (color, high resolution monochromatic, and infrared) on the E foot. Signals are telemetered to Sendai and Akita.

On 22 August, Tatsunori Soya, of the Geological Survey of Japan, drew attention to a document written by the late Prof. H. Tsuya. The document, which appeared in the Tamagawa Hot Spring Study Group's 10th Anniversary Report (1954), describes explosions in 1949, 1950, and 1951 at Akita-Yake-yama; the last two were not officially documented. According to the report, large explosion craters (C1-C4), including the Karanuma crater (C1), existed before the 1949 eruption. Eruptions in 1949 occurred on the E margin of the Karanuma crater, resulting in the formation of craters designated A1, A2, and A3. Although no one in the hot springs area 3 km E of the summit reported hearing an explosion or feeling earthquakes, the eruption products were ~1 m thick along the rim of the A1 crater and contained old lava blocks up to 1 m across. Another explosion occurred at the A1 crater in February 1951; as a result, A1 crater widened to become as much as 50 m across. In terms of volume, the 1951 explosion was smaller than the 1949 eruption. S. Hayashi proposed that the present explosion occurred in A2-A1, and mud spouted out from the A3 crater (figure 1).

Information Contacts: Shintaro Hayashi, Faculty of Education, Akita University, 1-1 Tegata-Gakuen-Cho, Akita 010, Japan; Noritake Nishide, Sendai District Meteorological Observatory, Japan Meteorological Agency, 1-3-5 Gorin, Miyagino-ku, Sendai 983 Japan; Volcano Research Center, University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html); Tatsunori Soya, Volcanology Section, Environmental Geology Department, Geological Survey of Japan, 1-1-3, Higashi, Tsukuba, Ibaraki, 305 Japan; Tsukasa Ohba and Toshiaki Hasenaka, Institute of Mineralogy, Petrology, and Economic Geology, Faculty of Science, Tohoku University, Miyagi, Sendai 980-77, 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.

Eruptive History

There is data available for 16 confirmed Holocene eruptive periods.

1997 Aug 16 - 1997 Aug 16 Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode Kare-numa
1997 Aug 16 - 1997 Aug 16 Evidence from Observations: Reported

List of 7 Events for Episode 1 at Kare-numa

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Seismicity (tremor)
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Ash weak or small
   - - - -    - - - - Earthquakes (undefined)
   - - - -    - - - - Crater Summit.
   - - - -    - - - - Lahar or Mudflow weak or small
1997 Aug 16    - - - - VEI (Explosivity Index)

1997 May 11 - 1997 May 11 Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode NE flank (Sumikawa-Onsen)
1997 May 11 - 1997 May 11 Evidence from Observations: Reported

List of 10 Events for Episode 1 at NE flank (Sumikawa-Onsen)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Seismicity (tremor) Before eruption.
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Avalanche
   - - - -    - - - - Ash
   - - - -    - - - - Lahar or Mudflow
   - - - -    - - - - Property Damage
   - - - -    - - - - Evacuations
1986 May 8    - - - - Fatalities
1988    - - - - Fatalities
1997 May 11    - - - - VEI (Explosivity Index)

1957 Jul 2 ± 182 days Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode
1957 Jul 2 ± 182 days - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity weak or small
   - - - -    - - - - Lahar or Mudflow weak or small
1957    - - - - VEI (Explosivity Index)

1951 Feb 16 ± 15 days Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode Kare-numa
1951 Feb 16 ± 15 days - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1 at Kare-numa

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
1951 Feb    - - - - VEI (Explosivity Index)

1950 Jul 2 ± 182 days Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode Kare-numa
1950 Jul 2 ± 182 days - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1 at Kare-numa

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
1950    - - - - VEI (Explosivity Index)

1949 Aug 30 - 1949 Sep 1 Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode Kare-numa
1949 Aug 30 - 1949 Sep 1 Evidence from Observations: Reported

List of 5 Events for Episode 1 at Kare-numa

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Ash
   - - - -    - - - - Blocks
   - - - -    - - - - Lahar or Mudflow
1949 Aug 30    - - - - VEI (Explosivity Index)

1948 Confirmed Eruption Max VEI: 1 (?)

Episode 1 | Eruption Episode Kare-numa
1948 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1 at Kare-numa

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity weak or small
1948    - - - - VEI (Explosivity Index)

1929 Sep Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1929 Sep - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity weak or small
   - - - -    - - - - Ash
1929 Sep    - - - - VEI (Explosivity Index)

1890 Sep 23 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1890 Sep 23 - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity weak or small
   - - - -    - - - - Ash
1890 Sep 23    - - - - VEI (Explosivity Index)

1887 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Karenuma
1887 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1 at Karenuma

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity weak or small
1887    - - - - VEI (Explosivity Index)

1867 Confirmed Eruption  

Episode 1 | Eruption Episode
1867 - Unknown Evidence from Observations: Reported

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity Uncertain

1678 Feb 22 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Karenuma
1678 Feb 22 (?) - Unknown Evidence from Observations: Reported

List of 5 Events for Episode 1 at Karenuma

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity
   - - - -    - - - - Tephra
   - - - -    - - - - Audible Sounds
   - - - -    - - - - Earthquakes (undefined) Before.
1678 Feb 22
(?)
   - - - - VEI (Explosivity Index)

1390 ± 75 years Confirmed Eruption  

Episode 1 | Eruption Episode
1390 ± 75 years - Unknown Evidence from Isotopic: 14C (calibrated)

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Phreatic activity

[ 0807 Nov 1 ] Uncertain Eruption

Episode 1 | Eruption Episode
0807 Nov 1 - Unknown Evidence from Unknown

List of 2 Events for Episode 1

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

0570 (?) Confirmed Eruption  

Episode 1 | Eruption Episode Ay-2 tephra
0570 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 3 Events for Episode 1 at Ay-2 tephra

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Phreatomagmatic
   - - - -    - - - - Tephra

1250 BCE ± 200 years Confirmed Eruption  

Episode 1 | Eruption Episode
1250 BCE ± 200 years - Unknown Evidence from Isotopic: 14C (calibrated)

List of 2 Events for Episode 1

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

3050 BCE (?) Confirmed Eruption  

Episode 1 | Eruption Episode Onigajo lava dome
3050 BCE (?) - Unknown Evidence from Radiogenic: Thermoluminescence

List of 1 Events for Episode 1 at Onigajo lava dome

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava dome
Deformation History

There is no Deformation History data available for Akita-Yakeyama.

Emission History

There is no Emissions History data available for Akita-Yakeyama.

GVP Map Holdings

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included. The maps database originated over 30 years ago, but was only recently updated and connected to our main database. We welcome users to tell us if they see incorrect information or other problems with the maps; please use the Contact GVP link at the bottom of the page to send us email.

Smithsonian Sample Collections Database

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

External Sites