Explosions cause ashfall in March and April
Card 1835 (01 April 1974) Large ash eruptions on 1 March from the E side of the central cone
After a long period of inactivity (since 1821), Tyokai volcano blew up on 1 March. Explosions at 1010 and 1130 (0110 and 0230 GMT) were the biggest, and repeated about ten times. Black smoke rose, and the volcanic ash fall lasted for ten minutes. According to aerial observations that same day, the eruption site was confirmed to be located on the eastern side of Sinzan, a central cone of this volcano. At first black smoke was spewing from the crater, and black ash was deposited on the eastern slope of the snow-covered volcano. According to an aerial observation on 3 March, this black smoke had turned into white vapor. Temporary seismic observations were carried out by the Tohoku University and the JMA around the skirt of this volcano, and scores of volcanic earthquakes were detected. A black belt (about 1.5 km long and 20-30 m wide) composed of ash-deposits and snow flowed down to the north side on 6 March. This belt is considered to be the result of a snow slide and there was no change or re-activity in the volcanic state. Gray volcanic smoke was observed on 5 March from the slope of the volcano, but there was no smoke after that.
Card 1850 (30 April 1974) Intermittent variable actiivty; ashfall on 24 April
The activity of Tyokai volcano started with the black smoke eruption and the volcanic ash fall on 1 March, but showed decreasing activity thereafter. Recently, however, the activity increased, and the following phenomena took place:
1) According to a visual observation on 8 April, and an aerial observation on 15 April, white smoke several tens of meters in height erupted from the new crater on the eastern flank of Sinzan, a central cone of this volcano, and white vapor about 20 m in height erupted from the 500 m long fissure on the western flank of Sinzan. On the fissure about ten fumaroles have formed.
2) On 24 April, black smoke, about several hundred meters in height, rose from the fissure on the W flank of Sinzan, and ash fell on the E foot of Tyokai volcano. On that day this black smoke gradually turned into white vapor. Simultaneously, a mud flow started from the summit crater and flowed down the W side, and this belt reached 3 km in length.
Information Contacts:
Card 1835 (01 April 1974) T. Tiba, Dept. of Geology, National Science Museum, Tokyu, Japan.
Card 1850 (30 April 1974) Seismological Division, JMA.
The Global Volcanism Program has no Weekly Reports available for Chokaisan.
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.
Explosions cause ashfall in March and April
Card 1835 (01 April 1974) Large ash eruptions on 1 March from the E side of the central cone
After a long period of inactivity (since 1821), Tyokai volcano blew up on 1 March. Explosions at 1010 and 1130 (0110 and 0230 GMT) were the biggest, and repeated about ten times. Black smoke rose, and the volcanic ash fall lasted for ten minutes. According to aerial observations that same day, the eruption site was confirmed to be located on the eastern side of Sinzan, a central cone of this volcano. At first black smoke was spewing from the crater, and black ash was deposited on the eastern slope of the snow-covered volcano. According to an aerial observation on 3 March, this black smoke had turned into white vapor. Temporary seismic observations were carried out by the Tohoku University and the JMA around the skirt of this volcano, and scores of volcanic earthquakes were detected. A black belt (about 1.5 km long and 20-30 m wide) composed of ash-deposits and snow flowed down to the north side on 6 March. This belt is considered to be the result of a snow slide and there was no change or re-activity in the volcanic state. Gray volcanic smoke was observed on 5 March from the slope of the volcano, but there was no smoke after that.
Card 1850 (30 April 1974) Intermittent variable actiivty; ashfall on 24 April
The activity of Tyokai volcano started with the black smoke eruption and the volcanic ash fall on 1 March, but showed decreasing activity thereafter. Recently, however, the activity increased, and the following phenomena took place:
1) According to a visual observation on 8 April, and an aerial observation on 15 April, white smoke several tens of meters in height erupted from the new crater on the eastern flank of Sinzan, a central cone of this volcano, and white vapor about 20 m in height erupted from the 500 m long fissure on the western flank of Sinzan. On the fissure about ten fumaroles have formed.
2) On 24 April, black smoke, about several hundred meters in height, rose from the fissure on the W flank of Sinzan, and ash fell on the E foot of Tyokai volcano. On that day this black smoke gradually turned into white vapor. Simultaneously, a mud flow started from the summit crater and flowed down the W side, and this belt reached 3 km in length.
Information Contacts:
Card 1835 (01 April 1974) T. Tiba, Dept. of Geology, National Science Museum, Tokyu, Japan.
Card 1850 (30 April 1974) Seismological Division, JMA.
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 |
||||
Tyokai | Tekai | Chokai-san | Dewa-Fuji | Akita-Fuji | Chokai | ||||
Cones |
||||
Feature Name | Feature Type | Elevation | Latitude | Longitude |
Higashi-Chokai | Stratovolcano | 2230 m | ||
Kannon-mori | Cone | 685 m | ||
Nishi-Chokai | Stratovolcano | |||
Craters |
||||
Feature Name | Feature Type | Elevation | Latitude | Longitude |
Saruana | Crater | |||
Tamano-ike | Crater | |||
Torinoumi | Crater | 1600 m | ||
Domes |
||||
Feature Name | Feature Type | Elevation | Latitude | Longitude |
Kojin-yama
Kozin-yama |
Dome | |||
Kyowa-yama | Dome | |||
Nabemori | Dome | |||
Sensumori | Dome | |||
Shin-zan
Sin-zan |
Dome | 2233 m | 39° 5' 47" N | 140° 3' 8" E |
|
|
There is data available for 14 confirmed Holocene eruptive periods.
1974 Mar 1 - 1974 Apr 30 Confirmed Eruption VEI: 1
Episode 1 | Eruption | E side of Shinzan, W of Kojin-yama | |||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1974 Mar 1 - 1974 Apr 30 | Evidence from Observations: Reported | |||||||||||||||||||||||||||||||||||||||
List of 6 Events for Episode 1 at E side of Shinzan, W of Kojin-yama
|
1834 Jul 9 - 1834 Jul Confirmed Eruption VEI: 2 (?)
Episode 1 | Eruption | ||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1834 Jul 9 - 1834 Jul | Evidence from Observations: Reported | |||||||||||||||||||||||||||||
List of 4 Events for Episode 1
|
1821 May 23 Confirmed Eruption VEI: 2 (?)
Episode 1 | Eruption | Near Shinzan and Shichiko-zan | |||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1821 May 23 - Unknown | Evidence from Observations: Reported | |||||||||||||||||||
List of 2 Events for Episode 1 at Near Shinzan and Shichiko-zan
|
1800 Dec - 1804 Jul (?) Confirmed Eruption VEI: 2
Episode 1 | Eruption | Shinzan (foot of Kojin-yama) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1800 Dec - 1804 Jul (?) | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
List of 13 Events for Episode 1 at Shinzan (foot of Kojin-yama)
|
[ 1764 ] Uncertain Eruption
Episode 1 | Eruption | ||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1764 - Unknown | Evidence from Unknown | |||||||||||||||||||||||||||||
List of 4 Events for Episode 1
|
1740 Jun (?) - 1747 (?) Confirmed Eruption VEI: 2 (?)
Episode 1 | Eruption | Small crater at foot of Kojin-yama | |||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1740 Jun (?) - 1747 (?) | Evidence from Observations: Reported | |||||||||||||||||||||||||||||
List of 4 Events for Episode 1 at Small crater at foot of Kojin-yama
|
[ 1738 Dec 31 ± 365 days ] Uncertain Eruption
Episode 1 | Eruption | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1738 Dec 31 ± 365 days - Unknown | Evidence from Unknown | |||||||||||||||||||
List of 2 Events for Episode 1
|
[ 1735 ] Uncertain Eruption
Episode 1 | Eruption | ||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1735 - Unknown | Evidence from Unknown | |||||||||||||||||||||||||||||
List of 4 Events for Episode 1
|
1659 Apr - 1663 ± 1 years Confirmed Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1659 Apr - 1663 ± 1 years | Evidence from Observations: Reported | ||||||||||||||
List of 1 Events for Episode 1
|
[ 1560 ] Uncertain Eruption
Episode 1 | Eruption | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1560 - Unknown | Evidence from Unknown | |||||||||||||||||||
List of 2 Events for Episode 1
|
[ 1477 ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1477 - Unknown | Evidence from Unknown | ||||||||||||||
List of 1 Events for Episode 1
|
[ 0999 ] Uncertain Eruption
Episode 1 | Eruption | ||||
---|---|---|---|---|
0999 - Unknown | Evidence from Unknown |
[ 0948 Dec 31 ± 365 days ] Uncertain Eruption
Episode 1 | Eruption | ||||
---|---|---|---|---|
0948 Dec 31 ± 365 days - Unknown | Evidence from Unknown |
0939 May 15 Confirmed Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0939 May 15 - Unknown | Evidence from Observations: Reported | ||||||||||||||
List of 1 Events for Episode 1
|
[ 0915 Aug 23 - 0915 Sep 1 ] Discredited Eruption
[ 0884 Jul 26 - 0884 Aug ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0884 Jul 26 - 0884 Aug | Evidence from Unknown | ||||||||||||||
List of 1 Events for Episode 1
|
0871 May 5 Confirmed Eruption VEI: 2
Episode 1 | Eruption | |||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0871 May 5 - Unknown | Evidence from Observations: Reported | ||||||||||||||||||||||||||||||||||
List of 5 Events for Episode 1
|
[ 0861 May ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0861 May - Unknown | Evidence from Unknown | ||||||||||||||||||||||||
List of 3 Events for Episode 1
|
[ 0857 May ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0857 May - Unknown | Evidence from Unknown | ||||||||||||||
List of 1 Events for Episode 1
|
[ 0856 ] Uncertain Eruption
Episode 1 | Eruption | ||||
---|---|---|---|---|
0856 - Unknown | Evidence from Unknown |
[ 0839 Oct 14 ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0839 Oct 14 - Unknown | Evidence from Unknown | ||||||||||||||
List of 1 Events for Episode 1
|
0830 Jan Confirmed Eruption
Episode 1 | Eruption | ||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0830 Jan - Unknown | Evidence from Observations: Reported | |||||||||||||||||||||||||||||
List of 4 Events for Episode 1
|
0817 ± 7 years Confirmed Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0817 ± 7 years - Unknown | Evidence from Observations: Reported | ||||||||||||||
List of 1 Events for Episode 1
|
[ 0804 - 0806 ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0804 - 0806 | Evidence from Unknown | ||||||||||||||
List of 1 Events for Episode 1
|
[ 0717 Jul ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0717 Jul - Unknown | Evidence from Unknown | ||||||||||||||
List of 1 Events for Episode 1
|
0711 ± 3 years Confirmed Eruption
Episode 1 | Eruption | |||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0711 ± 3 years - Unknown | Evidence from Observations: Reported | ||||||||||||||||||||||||
List of 3 Events for Episode 1
|
[ 0610 ± 18 years ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0610 ± 18 years - Unknown | Evidence from Unknown | ||||||||||||||
List of 1 Events for Episode 1
|
[ 0577 Dec 1 ± 30 days - 0578 Jul 15 ± 45 days ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0577 Dec 1 ± 30 days - 0578 Jul 15 ± 45 days | Evidence from Unknown | ||||||||||||||||||||||||
List of 3 Events for Episode 1
|
[ 0573 Mar (?) ] Uncertain Eruption
Episode 1 | Eruption | |||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0573 Mar (?) - Unknown | Evidence from Unknown | ||||||||||||||||||||||||||||||||||
List of 5 Events for Episode 1
|
0450 BCE (?) Confirmed Eruption
Episode 1 | Eruption | OD-12 tephra | |||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0450 BCE (?) - Unknown | Evidence from Correlation: Tephrochronology | |||||||||||||||||||
List of 2 Events for Episode 1 at OD-12 tephra
|
0650 BCE (?) Confirmed Eruption
Episode 1 | Eruption | Higashi-Chokai | ||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0650 BCE (?) - Unknown | Evidence from Isotopic: 14C (uncalibrated) | ||||||||||||||||||||||||||||||||||
List of 5 Events for Episode 1 at Higashi-Chokai
|
1050 BCE (?) Confirmed Eruption VEI: 0
Episode 1 | Eruption | West flank (Saruana crater) | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1050 BCE (?) - Unknown | Evidence from Correlation: Tephrochronology | ||||||||||||||||||||||||
List of 3 Events for Episode 1 at West flank (Saruana crater)
|
There is no Deformation History data available for Chokaisan.
There is no Emissions History data available for Chokaisan.
Maps are not currently available due to technical issues.
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.
There are no samples for Chokaisan in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.
Copernicus Browser | The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions. |
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. |
MODVOLC Thermal Alerts | 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. |
WOVOdat
Single Volcano View Temporal Evolution of Unrest Side by Side Volcanoes |
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.
GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments. |
Volcanic Hazard Maps | The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter. |
IRIS seismic stations/networks | Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Chokaisan. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice. |
UNAVCO GPS/GNSS stations | Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Chokaisan. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player. |
DECADE Data | The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO2 to the atmosphere, but installing CO2 monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere. |
Large Eruptions of Chokaisan | 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). |
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). |