Cite this Report
JMA reported that tremor was detected at Zaozan on 28 and 30 January, and minor inflation at the S part of the volcano was recorded. There were 12 volcanic earthquakes detected on 31 January. JMA raised the Alert level to 2 (on a 5-level scale), noting the increased potential for a small eruption.
Source: Japan Meteorological Agency (JMA)
Cite this Report
Earthquake and numerous aftershocks, but no surface changes evident
A seismic shock of M 4.7 occurred at 1758 on 1 September a few kilometers ESE of the summit. The shock was felt at JMA intensity IV near the volcano, and was weakly felt at Sendai (35 km E), Fukushima (45 km S), and Onahama (135 km E). Aftershocks were numerous, but declined toward mid-September. The high seismicity was the first at the volcano since July 1990, when there were many small earthquakes below the summit. Surveys of fumarolic areas on 5 September revealed no changes in temperature from the last survey in 1990.
Information Contacts: JMA.
2018: January
Cite this Report
JMA reported that tremor was detected at Zaozan on 28 and 30 January, and minor inflation at the S part of the volcano was recorded. There were 12 volcanic earthquakes detected on 31 January. JMA raised the Alert level to 2 (on a 5-level scale), noting the increased potential for a small eruption.
Source: Japan Meteorological Agency (JMA)
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.
Cite this Report
Earthquake and numerous aftershocks, but no surface changes evident
A seismic shock of M 4.7 occurred at 1758 on 1 September a few kilometers ESE of the summit. The shock was felt at JMA intensity IV near the volcano, and was weakly felt at Sendai (35 km E), Fukushima (45 km S), and Onahama (135 km E). Aftershocks were numerous, but declined toward mid-September. The high seismicity was the first at the volcano since July 1990, when there were many small earthquakes below the summit. Surveys of fumarolic areas on 5 September revealed no changes in temperature from the last survey in 1990.
Information Contacts: 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 |
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| Karita-dake | Kumano-dake | Gosei-dake | Kuraishi-dake | Tabashine-yama | Wasurezuno-yama | Zoo-dake | Taka-yama | Shiraishi-dake | Zao | ||||
Cones |
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| Feature Name | Feature Type | Elevation | Latitude | Longitude |
| Byobu-dake | Stratovolcano | 1817 m | ||
| Chuo-Zao | Stratovolcano | 1841 m | ||
| Fubo-san | Stratovolcano | 1705 m | ||
| Gando-san | Stratovolcano | |||
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Goshiki-dake
Gosiki-dake |
Tuff cone | 1674 m | ||
| Maeeboshi-dake | Stratovolcano | 1402 m | ||
| Manokami-dake | Stratovolcano | 1585 m | ||
| Minami-Zao | Stratovolcano | 1817 m | ||
| Nakamaru-yama | Stratovolcano | 1557 m | ||
| Nishi-Zao | Stratovolcano | 1364 m | ||
| Nonomori-yama | Stratovolcano | 733 m | ||
| Nyodo-san | Stratovolcano | 1600 m | ||
| Nyudo-san | Cone | 1640 m | ||
| Omori-yama | Cone | 820 m | ||
| Onmae-dake | Stratovolcano | 1705 m | ||
| Ryuzan | Stratovolcano | 1364 m | ||
| Sanpokojin-san | Stratovolcano | 1683 m | ||
| Sarukura-yama | Stratovolcano | 873 m | ||
| Sugigamine | Stratovolcano | 1745 m | ||
| Ushiroeboshi-dake | Stratovolcano | 1666 m | ||
| Yokokura-yama | Stratovolcano | 1152 m | ||
Craters |
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| Feature Name | Feature Type | Elevation | Latitude | Longitude |
|
Okama
Goshiki-numa Zao-numa |
Crater | 1674 m | ||
Domes |
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| Feature Name | Feature Type | Elevation | Latitude | Longitude |
| Jizo-san | Dome | 1694 m | ||
| Katta-dake | Dome | 1795 m | ||
| Kumano-dake | Dome | 1841 m | 38° 8' 26" N | 140° 26' 34" E |
| Torikabuto-yama | Dome | 1401 m | ||
Thermal |
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| Feature Name | Feature Type | Elevation | Latitude | Longitude |
| Aone Spa | Thermal | 520 m | ||
| Gaga Spa | Thermal | 800 m | ||
| Kamoshika | Thermal | 1150 m | ||
| Togatta Hot Spring | Hot Spring | |||
| Zao Spa | Thermal | 840 m | ||
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There is data available for 52 Holocene eruptive periods.
| Start Date | Stop Date | Eruption Certainty | VEI | Evidence | Activity Area or Unit |
|---|---|---|---|---|---|
| 1940 May 18 | 1940 May 18 | Confirmed | 1 | Historical Observations | Okama |
| [ 1939 Jul ] | [ Unknown ] | Uncertain | 1 | Okama | |
| [ 1927 ] | [ Unknown ] | Uncertain | 1 | Okama | |
| [ 1906 ] | [ Unknown ] | Discredited | |||
| 1905 | Unknown | Confirmed | 1 | Historical Observations | Okama |
| [ 1897 Jan 14 ] | [ 1897 Jan 14 ] | Uncertain | 1 | Okama | |
| [ 1896 Sep 1 (?) ] | [ Unknown ] | Uncertain | 1 | Okama | |
| 1896 Mar 8 | 1896 Mar 8 | Confirmed | 1 | Historical Observations | Okama |
| 1895 Aug 22 | 1895 Sep 28 | Confirmed | 2 | Historical Observations | Okama |
| 1895 Feb 15 | 1895 Mar 22 | Confirmed | 1 | Historical Observations | Okama |
| 1894 Jul 3 | 1894 Jul 3 | Confirmed | 2 | Historical Observations | Okama |
| [ 1890 ] | [ Unknown ] | Uncertain | 1 | Okama | |
| 1873 Aug | 1873 Sep | Confirmed | 1 | Historical Observations | Okama |
| 1867 Oct 21 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1833 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1831 Nov 22 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1830 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1822 May 1 | Unknown | Confirmed | Historical Observations | ||
| 1821 Jan 27 | 1821 May 1 | Confirmed | 2 | Historical Observations | Okama |
| 1809 Jun 12 | 1809 Dec 29 | Confirmed | 2 | Historical Observations | Okama |
| 1806 Jul 12 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1804 May (?) | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1796 Mar 24 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1794 Sep 22 | 1794 Dec (in or after) | Confirmed | 2 | Historical Observations | SE side of Okama |
| 1694 May 29 | 1694 Aug 30 (?) | Confirmed | 2 | Historical Observations | Okama |
| 1670 Apr 26 | 1670 Sep 26 | Confirmed | 2 | Historical Observations | Okama |
| 1669 | Unknown | Confirmed | 3 | Historical Observations | Okama |
| 1668 Aug | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1641 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1630 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1623 May 15 (?) | 1624 Nov 15 (?) | Confirmed | 3 | Historical Observations | Okama |
| 1622 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1620 | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1400 ± 100 years | Unknown | Confirmed | 3 | Radiocarbon (corrected) | Goshiki-dake area, Z-To11 tephra |
| [ 1350 (?) ] | [ Unknown ] | Uncertain | 2 | Okama | |
| [ 1331 ] | [ 1333 ] | Uncertain | 2 | Okama | |
| 1230 Nov 29 (?) | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 1227 Oct (?) | Unknown | Confirmed | 3 | Historical Observations | Okama |
| 1183 May 28 (?) | Unknown | Confirmed | 2 | Historical Observations | Okama |
| 0884 (?) | Unknown | Confirmed | 3 | Historical Observations | Okama, Z-To10 tephra? |
| [ 0773 Nov (?) ] | [ Unknown ] | Uncertain | Okama | ||
| 0300 ± 200 years | Unknown | Confirmed | 4 | Radiocarbon (corrected) | Goshiki-dake area, Z-To9 tephra |
| 1600 BCE (?) | Unknown | Confirmed | Radiocarbon (corrected) | Goshiki-dake | |
| 2000 BCE ± 500 years | Unknown | Confirmed | Tephrochronology | Goshiki-dake | |
| 2300 BCE ± 75 years | Unknown | Confirmed | Radiocarbon (corrected) | Goshiki-dake area, Z-To8 tephra | |
| 2600 BCE ± 200 years | Unknown | Confirmed | Radiocarbon (corrected) | Goshiki-dake area, Z-To7 tephra | |
| 3350 BCE ± 50 years | Unknown | Confirmed | Radiocarbon (corrected) | Goshiki-dake area, Z-To6 tephra | |
| 3850 BCE ± 200 years | Unknown | Confirmed | Radiocarbon (corrected) | Goshiki-dake area, Z-To5 tephra | |
| 4150 BCE ± 200 years | Unknown | Confirmed | Radiocarbon (corrected) | Goshiki-dake area, Z-To5b tephra | |
| 5500 BCE (?) | Unknown | Confirmed | Radiocarbon (corrected) | Goshiki-dake area | |
| 5600 BCE (?) | Unknown | Confirmed | Radiocarbon (corrected) | Goshiki-dake, Z-To5a tephra | |
| 7600 BCE (?) | Unknown | Confirmed | Radiocarbon (corrected) | Goshiki-dake area |
There is data available for 1 deformation periods. Expand each entry for additional details.
| Start Date: 2011 Mar 11 | Stop Date: 2011 Mar 11 | Direction: Subsidence | Method: InSAR |
| Magnitude: 8.000 cm | Spatial Extent: 20.00 km | Latitude: 38.000 | Longitude: 140.000 |
Remarks: Subsidence of plutonic bodies triggered by Mw 9.0 Tohoku earthquake | |||
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Close-up interferograms. Blue squares indicate geothermal power plants. GEONET stations are indicated by numbered circles, with the colour inside indicating the GPS displacements in the LOS direction. From: Takada and Fukushima 2013. |
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Reference List: Takada and Fukushima 2013; Ozawa and Fujita 2013.
Full References:
Ozawa T, Fujita E, 2013. Local deformations around volcanoes associated with the 2011 off the Pacific coast of Tohoku earthquake. J. Geophys. Res., 118, 390-405. https://doi.org/10.1029/2011JB009129
Takada and Fukushima, 2013. Volcanic subsidence triggered by the 2011 Tohoku earthquake in Japan. Nature Geoscience, 6: 637-641.
There is no Emissions History data available for Zaozan [Zaosan].
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.
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Title: Computer Generated Geologic Map of Japan Publisher: Geological Survey of Japan Country: Japan Year: 1990 Series: No 22 Map Type: Geology Scale: 1:2,000,000 |
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Title: Japan, South Korea Publisher: DMA Aerospace Center Country: Japan, S Korea Year: 1988 Series: ONC Map Type: Topographic Scale: 1:1,000,000 |
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Title: (A) Q Maps of Japan Landforms, Geol, Tect: NEast Publisher: Univ of Tokyo Press & Japan Association for Quaternary Research Country: Japan Year: 1987 Map Type: Geology Scale: 1:1,000,000 |
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Title: (B) Q Maps of Japan Landforms, Geol, Tect: Central Publisher: Univ of Tokyo Press & Japan Association for Quaternary Research Country: Japan Year: 1987 Map Type: Geology Scale: 1:1,000,000 |
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Title: Japan Publisher: DMA Aerospace Center Country: Japan Year: 1985 Series: TPC Map Type: Topographic Scale: 1:500,000 |
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Title: Historical Japan Publisher: National Geographic Society Country: Japan Year: 1984 Series: National Geographic Map Type: Geographic Scale: 1:2,982,000 |
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Title: Geol Map of Japan/ Geol Atlas Publisher: Geol Survey of Japan Country: Japan Year: 1982 Map Type: Geology Scale: 1:1,000,000 |
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Title: North Japan Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1980 Map Type: Topographic Scale: 1:1,000,000 |
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Title: North Japan Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1980 Map Type: Topographic Scale: 1:1,000,000 |
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Title: Central Japan Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1980 Map Type: Topographic Scale: 1:1,000,000 |
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Title: Central Japan Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1980 Map Type: Topographic Scale: 1:1,000,000 |
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Title: Central Japan Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1980 Series: CIM 1:1 mil Map Type: Topographic Scale: 1:1,000,000 |
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Title: North Japan Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1980 Series: CIM 1:1 mil Map Type: Topographic Scale: 1:1,000,000 |
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Title: Geological Map of Japan Publisher: Geological Survey of Japan Country: Japan Year: 1978 Map Type: Geology Scale: 1:1,000,000 |
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Title: Geological Map of Japan Publisher: Geological Survey of Japan Country: Japan Year: 1978 Map Type: Geology Scale: 1:1,000,000 |
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Title: Geological Map of Japan Publisher: Geological Survey of Japan Country: Japan Year: 1978 Map Type: Geology Scale: 1:1,000,000 |
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Title: Distribution Map of Hot Springs in Japan Publisher: Geological Survey of Japan Country: Japan Year: 1975 Series: 1:2,000,000 Map Type: Unknown Scale: 1:2,000,000 |
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Title: (Japanese) Geol map of Japan Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1974 Series: from Natl Atlas Japan Map Type: Geology Scale: 1:2,500,000 |
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Title: Landform Classification Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1972 Series: from Natl Atlas Japan Map Type: Unknown (Land) Scale: 1:2,500,000 |
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Title: Land Use Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1972 Series: from Natl Atlas Japan Map Type: Unknown (Land) Scale: 1:2,500,000 |
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Title: Population Distribution Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1972 Series: from Natl Atlas Japan Map Type: Unknown Scale: 1:2,500,000 |
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Title: River Systems Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1972 Series: from Natl Atlas Japan Map Type: Unknown Scale: 1:2,500,000 |
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Title: Central Japan Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1966 Map Type: Topographic Scale: 1:1,000,000 |
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Title: North Japan Publisher: Geographical Survey Institute of Japan Country: Japan Year: 1966 Map Type: Topographic Scale: 1:1,000,000 |
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Title: Sendai Publisher: US Army Map Service Country: Japan Year: 1954 Series: AMS Map Type: Topographic Scale: 1:250,000 |
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Title: Numasawa-Numa Publisher: US Army Map Service Country: Japan Year: 1945 Series: AMS Map Type: Topographic Scale: 1:250,000 |
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Title: Sendai Publisher: US Army Map Service Country: Japan Year: 1943 Series: AMS Map Type: Topographic Scale: 1:1,000,000 |
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There are no samples for Zaozan [Zaosan] in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.
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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. |
| 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. |
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Sentinel Hub Playground
Sentinel Hub EO Browser |
The Sentinel Hub Playground provides a quick look at any Sentinel-2 image in any combination of the bands and enhanced with image effects; Landsat 8, DEM and MODIS are also available. Sentinel Hub is an engine for processing of petabytes of satellite data. It is opening the doors for machine learning and helping hundreds of application developers worldwide. It makes Sentinel, Landsat, and other Earth observation imagery easily accessible for browsing, visualization and analysis. Sentinel Hub is operated by Sinergise |
| 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 Zaozan [Zaosan]. 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 Zaozan [Zaosan]. 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 Zaozan [Zaosan] | 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). |
Okama crater of Goryudake within the Zaozan volcanic complex is shown here from the E. The 360-m-wide lake is about 60 m deep and is the site of many historical eruptions. White mud deposited on the lake floor is periodically disturbed by gas emission, changing the color of the water. The Zao volcano group, the most active of northern Honshu, consists of a complex cluster of cones straddling the Pacific Ocean-Japan Sea divide.
