Global Volcanism Program

The Global Volcanism Program has no activity reports available for Myokosan.

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

The Global Volcanism Program has no Bulletin Reports available for Myokosan.

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

Myoko

Domes

Feature Name

Feature Type

Elevation

Latitude

Longitude

Myokosan
Shin-yama

Dome

Thermal

Feature Name

Feature Type

Elevation

Latitude

Longitude

Akakura

Thermal

Tsubame

Thermal

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude

283100

750 BCE

2,454 m / 8,051 ft

36.891°N
138.114°E

Morphology

Volcano Landform
Composite

Volcano Types
Stratovolcano
Caldera
Lava dome

Rock Types

Major
Andesite / Basaltic Andesite
Dacite
Basalt / Picro-Basalt

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Population

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

1,563
11,033
561,142
4,118,863

Geological Summary

Myokosan is a steep-sided basaltic-to-dacitic stratovolcano north of Nagano City that overlooks Lake Nojiri below its SE flank. A 3-km-wide caldera breached widely to the east is filled by a flat-topped lava dome that forms the summit. It was constructed during four stages beginning about 300,000 years ago, each evolving from basaltic to andesitic and dacitic eruptions. The latest eruptive stage began about 43,000 years ago. Several episodes of edifice collapse during the late Pleistocene to early Holocene have produced major debris avalanches that traveled to the E and NE. Pyroclastic flows traveled down the eastern flanks during the mid-Holocene about 5,800 and 4,200 years ago, and the latest dated eruption produced pyroclastic surges about 2,800-2,500 years ago. Constant solfataric activity occurs between the dome and the south caldera wall at a place where sulfur was once mined.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Hayatsu K, 1976. Geologic study on the Myoko volcanoes, central Japan - Part 1. Stratigraphy. Kyoto Univ Ser Geol Min, 42: 131-170.

Hayatsu K, 1985. Myoko volcano group - its geology and history. Tokyo: Daiichi-Shuppan, 344 p (in Japanese).

Hayatsu K, Arai F, 1980. Tephrochronological study on the Myoko volcano tephra layers and their relation to activity of the volcano. J Geol Soc Japan, 86: 243-263 (in Japanese with English abs).

Hayatsu K, Shimizu S, Itaya T, 1994. Volcanic history of the Myoko volcano group, central Japan; a poly-generation volcano. J Geogr, 103: 207-220 (in Japanese with English abs).

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.

Kawachi S, Hayatsu K, 1994. Debris avalanche and lahar deposits in the Yatsugatake volcanic chain and Myoko volcano, central Japan. J Nat Disaster Sci, 16: 55-69.

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, https://gbank.gsj.jp/volcano/index_e.htm.

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/.

Eruptive History

There is data available for 10 confirmed Holocene eruptive periods.

0750 BCE Confirmed Eruption

Episode 1 | Eruption

0750 BCE - Unknown

Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1

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

1200 BCE (?) Confirmed Eruption

Episode 1 | Eruption

1200 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1

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

2100 BCE ± 500 years Confirmed Eruption

Episode 1 | Eruption

2100 BCE ± 500 years - Unknown

Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1

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

2750 BCE ± 100 years Confirmed Eruption VEI: 4

Episode 1 | Eruption

Otagirigawa Ash; OT-a tephra

2750 BCE ± 100 years - Unknown

Evidence from Isotopic: 14C (calibrated)

List of 6 Events for Episode 1 at Otagirigawa Ash; OT-a tephra

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Phreatic activity
- - - -	- - - -	Phreatomagmatic
- - - -	- - - -	Pyroclastic flow
- - - -	- - - -	Ash
2750 BCE ± 100 years	- - - -	VEI (Explosivity Index)

2900 BCE (?) Confirmed Eruption

Episode 1 | Eruption

2900 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1

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

3450 BCE (?) Confirmed Eruption

Episode 1 | Eruption

3450 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Explosion
	- - - -	- - - -	Pyroclastic flow

3700 BCE (?) Confirmed Eruption

Episode 1 | Eruption

3700 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Explosion
	- - - -	- - - -	Pyroclastic flow

4000 BCE (?) Confirmed Eruption

Episode 1 | Eruption

4000 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1

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

4300 BCE (?) Confirmed Eruption

Episode 1 | Eruption

4300 BCE (?) - Unknown

Evidence from Correlation: Tephrochronology

List of 3 Events for Episode 1

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Lava flow
- - - -	- - - -	Ash

4750 BCE ± 300 years Confirmed Eruption VEI: 5 (?)

Episode 1 | Eruption

Akakura Ash; AK-a tephra

4750 BCE ± 300 years - Unknown

Evidence from Isotopic: 14C (calibrated)

List of 6 Events for Episode 1 at Akakura Ash; AK-a tephra

Start Date	End Date	Event Type	Event Remarks
- - - -	- - - -	Explosion
- - - -	- - - -	Phreatic activity
- - - -	- - - -	Pyroclastic flow
- - - -	- - - -	Lava flow	Uncertain
- - - -	- - - -	Ash
4750 BCE ± 300 years	- - - -	VEI (Explosivity Index)

Deformation History

There is no Deformation History data available for Myokosan.

Emission History

There is no Emissions History data available for Myokosan.

Photo Gallery

Myoko, located in west-central Honshu, has a 3-km-wide caldera that is partially filled by a summit lava dome. Several edifice collapse events at Myoko have produced major debris avalanches that traveled to the E and NE.

Photo by Yukio Hayakawa, 1998 (Gunma University).

GVP Map Holdings

Maps are not currently available due to technical issues.

Smithsonian Sample Collections Database

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

External Sites

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 Myokosan. 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 Myokosan. 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 Myokosan

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).